3 1 " ?

AS/ svo. 79 CS"

LIFE HISTORY OF Mayatrichia ponta ROSS (TRICHOPTERA:

HYDROPTILIDAE) IN HONEY CREEK, TURNER FALLS PARK,

OKLAHOMA

THESIS

Presented to the Graduate Council of the

University of North Texas in Partial

Fulfillment of the Requirements

For the Degree of

MASTER OF SCIENCE

By

Yi-Kuang Wang, B.S.

Denton, Texas

December, 1997

\

Wang, Yi-Kuang, Life history of Mayatrichia ponta Ross (Trichoptera:

Hvdroptilidae) in Honey Creek. Turner Falls Park. Oklahoma. Master of Science

(Biology), December, 1997, 56 pp., 12 illustrations, references, 72 titles.

The life history and ontogenetic microhabitat change of Mayatrichia ponta Ross

were investigated in Honey Creek, Turner Falls Park, Murray Co., Oklahoma, U.S.A.

from August 1994 to August 1995. The shape of larval cases changed from a small cone

to a cylinder. M. ponta had an asynchronous multivoltine life history with considerable

cohort and generation overlap; five generations were estimated. The development rate

was reduced in winter. The winter generations of M. ponta had wider head capsule

widths (136 - 165 /i.m) than summer generations (121 - 145 ^m). The sex ratio of adults

was 1.43

3 1 " ?

AS/ svo. 79 CS"

LIFE HISTORY OF Mayatrichia ponta ROSS (TRICHOPTERA:

HYDROPTILIDAE) IN HONEY CREEK, TURNER FALLS PARK,

OKLAHOMA

THESIS

Presented to the Graduate Council of the

University of North Texas in Partial

Fulfillment of the Requirements

For the Degree of

MASTER OF SCIENCE

By

Yi-Kuang Wang, B.S.

Denton, Texas

December, 1997

ACKNOWLEDGMENTS

I thank my Major Professor: Dr. J. H. Kennedy and my Graduate Committee: Drs.

K. W. Stewart and K. L. Dickson for their assistance and support. I wish to express

appreciation to my parents, Shin-Liang Wang and Shu-Inn Chin, for encouragement and

support throughout this study. Help and comments by Dr. S. R. Moulton II were very

helpful. Thanks to Turner Falls Park, Davis City, OK., allowing access to their property.

I also thank the Illinois Natural History Survey for lending M. ayama specimens to

compare with M. ponta. I appreciate the help and comments provided by the following

people: J. D. Csekitz, R. E. Cook, Dr. A. Goven, B. T. Hall, D. C. Houghton, Z. B.

Johnson, V. Kennedy.

111

TABLE OF CONTENTS

Page

LIST OF FIGURES v

Chapter

1. INTRODUCTION 1

2. MATERIALS AND METHODS 6

Study Site and Sampling

Adults Larvae Microhabitat Rearing

3. RESULTS AND DISCUSSION 11

Larval Description Pupal Description Female Description Egg Larval Microhabitat Larval Case and Behavior Emergence and Flight Periodicity Fecundity Life History and Larval Growth

APPENDIX 22

LITERATURE CITED 48

IV

LIST OF FIGURES

Figure Page

1. Location of study area in Honey Creek, Murray County, Oklahoma 23

2. Water temperature of Honey Creek measured on sampling dates 25

3. A plastic-bag flow meter, modified from Gessner( 1955). Scale bar = 5 cm 27

4. Scatter plot of M. ponta head capsule width against length 29

5. Instars of M. ponta: A. instar I; B. instar IV. Scale bars = 0.1 mm 31

6. Instar V of M. ponta: A. Head (dorsal); B. Thoracic nota (left side); C. Anal claw (lateral ventral side on the top); D. Thoracic legs (right lateral). Scale bars = 0.1 mm

33

7. Pupa of M. ponta-, A. labrum, scale bar = 0.1 mm; B. mandible, scale bar = 0.1 mm; C. abdomen (dorsal), scale bar = 1mm; D. denticles, scale bar = 0.05 mm 35

8. Pupal case of M. ponta (lateral). Scale bar = 1 mm 37

9. Female genitalia of M. ponta (ventral): A. terminal abdominal segments; B. bursa copulatrix. Scale bars = 1 mm. Abbreviations: VI-X = abdominal segments VI-X 39

10. Plot of instar mean density with standard deviation on different sides of rocks: A. instar I; B. instar II; C. instar III; D. instar IV; E. instar V; F. pupae. ( • indicates statistically different group, SNK, a = 0.05) 41

11. Fecundity (mean ± 1 S.D.) of M. ponta 44

12. Relative abundance of instars and pupae, and adult abundance through August 1994 to August 1995. Width of bars = relative percent of each instar or pupae represented. Each cohort indicates by a curved line and peak oviposition by arrows 46

CHAPTER 1

INTRODUCTION

Life history information is of fundamental importance for virtually all aquatic

ecological studies (Butler 1984). Understanding life history information facilitates the

development of appropriate sampling strategies for aquatic ecological research (Resh

1979). The impacts of human activities on animal populations can be reliably assessed

with life stage knowledge (Ward 1976, Lehmkuhl 1979, Wallace 1990). Life history

information can help the selection or design of toxicity tests (Buikema and Benfield

1979). Life history studies also contribute to taxonomy by providing supporting or

clarifying information about existing taxoaomy or suggesting reevaluation (Oliver 1979).

From a conservation viewpoint, life history information helps scientists develop

management strategies for aquatic systems.

The term life cycle is often confused with fife history. A life cycle is the sequence

of morphological stages and physiological processes that link one generation to the next,

for instance egg, larval, pupal and adult stages, metamorphosis, dormancy, feeding,

regional dispersal, and reproduction (Butler 1984). Life history involves the qualitative

and quantitative details of the variable events associated with the life cycle, including

fecundity, growth phenology and rate, mortality, and emergence patterns (Butler 1984).

Life history patterns of aquatic insect species are selectively controlled by intrinsic and

extrinsic factors (Williams 1991). Intrinsic factors, such as physiology, behavior, and

2

morphology, often restrict life history traits within certain genetically determined ranges

(Williams 1991). Extrinsic factors include biotic and abiotic categories. Abiotic factors,

including water quality, photoperiod, habitat, and especially temperature, can influence

the distribution, development, and voltinism of aquatic insects (T'rapp 1991). Biotic

factors, such as predation (Butler 1984, Martin et al. 1991), food quality and quantity, and

intra- and interspecies competition (Townsend and Hildrew 1979, Goddeeris 1987), can

lead to selectively driven evolution.

The insect order Trichoptera, or caddisflies, is a sister group of Lepidoptera

(Hennig 1981), with holometabolous metamorphosis. Caddisflies represent one of the

most successful aquatic insect orders in terms of diversity, having more species than any

other aquatic order (Mackay and Wiggins 1979). Caddisflies inhabit most freshwater

habitats and occupy every trophic level and feeding category in freshwater communities

(Mackay 1979, Mackay and Wiggins 1979, Wells 1992, Whitlock and Morse 1994).

A checklist of North American Trichoptera fauna (including Greenland and

Mexico) at the end of 1992 listed 1,653 species classified in 164 genera in 24 families

(Morse 1993). According to Wiggins (1990), only about 370 (28%) of the 1340 North

American species larvae have been described. Larvae of unproven taxonomic identity

continue to be the building blocks of Trichoptera study (Wiggins 1996a).

The family Hydroptilidae belongs to the most primitive suborder Spicipalpia,

superfamily Hydroptiloidea (Wiggins and Wichard 1989, Frania and Wiggins 1995). The

Hydroptilidae was first designated by F.J. Pictet (1834). Because the lengths of larvae

and adults are usually less than 6 mm, they are also called microcaddisflies. The family,

3

represented by 308 species, is the largest in the order (Morse 1993), accounting for about

22% of Nearctic Trichoptera (Wiggins 1996a). As of 1987 (Wiggins 1990), larvae of

only 28 (12.3%) of the 220 hydroptilid species north of Mexico in North America were

known.

The genus Mayatrichia was first established in 1937, with defining characteristics

of 0-2-4 tibial spurs and three ocelli (Mosely 1937). The genus is in the tribe Neotrichiini

under the subfamily Hydroptilinae. Mayatrichia has six species distributed over North

and Central America, and northern South America. The attenuated head of Mayatrichia

larvae, which suggests specialized feeding behavior, might also be related to the

construction of the unusual case (Wiggins 1996a). Wiggins (1996b) indicated that

Mayatrichia species are scrapers and dingers.

Mayatrichia ponta Ross was first described from specimens collected along the

Honey Creek segment in Turner Falls Park, Oklahoma (Ross 1944). The adults have also

been reported in Oklahoma, Texas, and Wyoming (Moulton and Stewart 1996, Moulton

and Stewart 1997). The last instar larvae were associated with adults by Wiggins

(1996a). The case of M. ponta is constructed of silk and often covered with calcium

carbonate precipitation. The case wall usually has a pair of external ventrolateral ridges

(Wiggins 1996b). The male of this species is most closely related to the Mexican

Mayatrichia rualda Mosely, and differs by having three rather than two large setae on

each clasper, and in the shape of sclerites of the genital capsule (Ross 1944). The

posterolateral margin of abdomen segment IX of M. ponta is produced into a mitten-like

projection, and the ventral lobe is thumb-like (Ross 1944, Moulton and Stewart 1996).

The female of M. ponta was undescribed before this study. Adults were present in

February, May, June, and August in the Interior Highlands (Moulton and Stewart 1996).

Larval hydroptilids are free-living for the first four instars and cased in the fifth

instar (Wiggins 1996a). The morphology and behavior of the first four instars differ

greatly from the fifth, and this is called heteromorphosis (Nielsen 1948). Hydroptilids

spend more time in the last instar than in the first four, and can grow from first instar to

the last within three weeks; this unique developmental cycle is called

hypermetamorphosis (Needham 1902, Nielsen 1948). After molting to the fifth instar, the

larva constructs a barrel-shaped or purse-shaped case with sand, algae, or debris. Some

last instar hydroptilid larvae are sessile, while others are mobile. Mature larvae attach

their cases to substrates with silk, seal the openings, and pupate inside.

There are only two published detailed studies of hydroptilid life histories in North

America. Leucotrichia pictipes Banks was univoltine with an overwintering final instar

in Montana (McAuliffe 1982). Resh and Houp (1986) reported a univoltine cycle for

Dibusa angata Ross in Kentucky. D. angata had an egg diapause in the summer and

autumn, hatching started at mid-November, and emergence occurred from April to May.

There are other non-detailed published hydroptilid studies. Recasens and Puig

(1991) reported bivoltinism for Hydroptila insubrica Ris, possibly three generations per

year for Hydroptila martini Marshall, and a univoltine life history for Hydroptila vectis

Curtis and Oxythira frici K1 from the Matarrana river, NE Spain. Nielsen (1948) reported

Agraylea, Hydroptila, and Oxythira as having bivoltinism in Denmark. Wells (1985)

reported univoltine to multivoltine life histories for Australian hydroptilids, but gave no

5

details. There has been no reported life history study of any species in the genus

Mayatrichia.

Microhabitat

Many animals change their habitats or diets during development (Martin 1966,

Clark and Gibbson 1969, Fedorenko 1975, Pianka 1976, Neill and Peacock 1980, Wilbur

1980, Mushinsky et al. 1982, Polis 1984). Ontogenetic behaviors are hypothesized as

mechanisms to minimize intraspecific competition (Keast 1977). Size-specific dietary

shifts are often associated with or caused by shifts in habitat (Werner and Gilliam 1984).

A few studies have examined the shifts of microhabitats related to flow through larval

development of aquatic insects (Boon 1979, Osborne and Herricks 1987, Muotka 1990,

Poff and Ward 1992).

Research Objectives

Mayatrichia ponta is abundant in travertine Honey Creek. The purpose of my

research is to provide descriptions of the life cycle and life history of M. ponta, and to

describe the female for the first time.

During the process of field sampling, I observed that M. ponta pupae frequently

aggregated on the bottom of substrates. To support this observation, I decided to

quantitatively study the distribution patterns of instars and pupae on different sides of

rocks. This may help in an understanding of intra- and inter-specific population

dynamics of this species.

CHAPTER 2

MATERIALS AND METHODS

Study Site and Sampling

Honey Creek is a second order permanent limestone stream, originating in the

Arbuckle mountains, and flowing northeastward into the Washita River. The geological

formation of Honey Creek changes sequentially from cherty limestone and sandstone to

'Fernvale' limestone and, eventually, to Washita alluvium (Ham 1969). Honey Creek

descends from an elevation of 420 meters at its origin to the Washita River at 235 meters

(Ham 1969). The most rapidly descending areas are the Bridal Veil Falls and Turner

Falls. The pH, raised by photo-synthetic activity from aquatic plants and algae, causes

precipitation of calcium and magnesium carbonates to form thick layers of travertine in

the study area (Minkley 1963).

The study riffles were within a 900 meter zone upstream of Bridal Veil Falls in

Turner Falls Park (Fig. 1). The upstream riffles were mainly composed of cobbles and

pebbles; downstream riffles were mainly composed of travertine substrates with sparse to

aggregated stones. The creek width ranged from 15 to 30 meters. Riffle depth ranged

from 1 to 2 cm in travertine bed reaches to 20 cm in cobble substrate reaches under base

flow condition.

The physical, chemical, and biological components of this site have been studied

by Reisen(1975, 1976); the mean pH was 8, mean D.O. 9.2 mg/1, and mean discharge

7

1.06 (m3/sec). Nitrate level ranged from 0.11 to 0.15 mg/1. Orthophosphate

concentration ranged from 0.5 to 1.3 mg/L.

Water temperature of Honey Creek ranged from 9 °C in the winter to 25 °C in the

summer during the study period (Fig. 2). Air temperature ranged from -6.7 to 41 °C.

Samples of larvae, pupae, and adults were taken from August, 1994 until August,

1995, weekly from August to September 1994, and biweekly for remainder of the study

duration. All statistical analyses followed Zar (1984) using SAS software (1991).

Adults

M. ponta adults were collected with an 8-Watt UV light during each field trip.

The trap was set approximately one meter from the shoreline near downstream riffles.

The light was operated for one hour after sunset. Aerial nets were also used to collect

adults. Flight periodicity was determined from these samples. Fecundity was studied by

dissection of field-collected females, and lab-reared females when no adults were caught

by light traps. Adults of M. ponta were studied and illustrated using an Olympus

compound microscope and attached drawing tube. Individuals were prepared for

illustration by soaking in 10% potassium hydroxide for approximately one day, and were

neutralized in 10% Hydrochloric acid. Specimens were soaked in Ethylene Glycol

Monomethel Ether before mounting in Canadian balsam.

Larvae

Preliminary samples indicated that the majority of M. ponta larvae were found on

rocks resting on the travertine stream substrates. They were collected from rock surfaces

for growth analysis. On each sampling date, six rocks ranging from 15 to 30 cm across

were collected. Organisms and debris on the surface of the rock were brushed into a

bucket filled with stream water. A 150 /im sieve was initially used for collection in

August 1994. Subsequent sampling used a 38 /urn sieve to collect early instars.

Collected materials were preserved in Kahle's solution. Samples were stored in 80%

ethanol until studied in the laboratory.

Head capsule of larvae were measured using an Olympus SZH dissecting

microscope coupled with an Olympus CUE-2 image processing system. Instars were

separated by a scatter plot of head capsule width against head length. The prominent

sclerites of the fifth instar were used to distinguish instars of this species. The length of

the head capsule (HCL) was measured from the anterior margin of the frons to the

posterior margin of head sclerites. The width of the head (HCW) was measured as the

distance of the head capsule across the eyes. Larvae, cases, and pupae were studied and

illustrated for description using the same procedure as for adults.

Larvae preserved in ethanol and carbonated water were used for diet examination.

Fore- and midguts were dissected, placed in glycerin on a microscope slide and scanned

under a compound microscope at 100X. The proportions of diet were quantified by

relative percentage of area.

Microhabitat

Spatial distributions of M. ponta larvae and pupae were determined on each

surface (top, bottom, front, back, left, and right) of individual rocks. This sampling

occurred in March, 1996, a period with high numbers of larvae and pupae. Prior to each

biological sampling, water flows were estimated in front of individual rocks by a Pygmy

9

flow meter and each exposed rock surface using a modified Gessner current meter (Fig.

3) (Gessner 1955, Hynes 1970, Wallace 1975). The diameter of opening of the Gessner

flow meter was 0.6 cm. These measurements were used to examine the effects of current

speed have on the distribution of M. ponta on rock surfaces. After measuring currents, all

organisms and materials were brushed from each rock surface, concentrated in a sieve (38

|um), and preserved with Kahles solution in separate bottles. Larvae were sorted to instar

and counted in the lab. The area of each side of the rock was measured using aluminum

foil weight-area method described by Doeg and Lake (1981).

Individual counts of each instar and pupae were converted to a standard density,

No./0.01m2, based on the mean area of each surface for all stones collected. Current

velocities of rock surfaces were normally distributed (Shapiro-Wilk test for normality, a

= 0.05). A one-way ANOVA was used to test if the means of current velocities on six

sides were significantly different. Both population size and surface area data were

normally distributed. A Pearson Correlation Analysis was used to examine the

coefficient between the population size of M. ponta and surface area on substrates. A

one-way ANOVA was also used to examine the mean densities of each instar of on the

six sides. The Student-Newman-Kuels multiple comparison test was used to separate

means into groups when statistical significant occurred.

Rearing

Attempts were made to collect fertilized eggs from live M. ponta females

collected in the field. Eggs were also collected from reared females. Eggs obtained were

incubated in an environmental growth chamber with simulated stream photoperiod and

10

temperature to obtain first instar larvae.

Live larvae and pupae were reared in aquaria containing natural substrates and

aerated stream water. Pupae were reared individually in a punctured plastic bag to

associate with adults. Larval and adult behaviors were observed in these aquaria. Larval

behaviors were also observed under a dissecting microscope.

The overall behavior, fecundity, life cycle, voltinism, and life history of M. ponta

were interpreted from information gathered by the above described field activities and

laboratory observations. Voucher materials, including representatives of all life stages,

were deposited in the University of North Texas Water Research Field Station Collection.

CHAPTER 3

RESULTS AND DISCUSSION

Despite numerous attempts to induce oviposition in laboratory-reared or field

collected females, eggs were not successfully hatched. Therefore, first instar larvae were

not positively established by rearing. Mayatrichia ponta is the dominant species in my

samples. The presence of other hydroptilids were examined and compared. Presumed M.

ponta first instar were abundant following peak emergence and before the appearance of

later instars. The larvae and pupae of Mayatrichia ayama Mosely specimens were also

examined. Nothing similar to M. ayama larvae or pupae was found in my samples.

Instars were separated by a scatter plot of head capsule width against head capsule

length (Fig. 4) Head widths of instar IV overlapped with instar V, however, head lengths

of these instars were distinct and not overlapped.

Larval description

Presumed first instar larvae bearing many hairs (Fig. 5A). Anal claws broadly

joined to the abdomen. Three caudal gill filaments. Tibial claws with an array of short

hairs.

Instars II to IV with similar setal pattern on abdomens (Fig. 5), but without hairs

on tibial claws. Setae and dorsal sclerites developing through growth. Head capsule

11

12

developing toward cone shape (Fig. 5, Fig. 6). Three gill filaments present.

Fourth instar (Fig. 5B) very similar to the terminal instar. Setae stout and short

relative to body size. Sclerites present on thoracic terga and transparent.

Instar V (Fig. 6) similar to drawings of Wiggins (1996b), but with more setae on

head and thorax. The front fringes of dorsal sclerites bearing a row of large setae.

Sclerites with many small setae scattered. Thorax well scleritized and covered. Sclerites

brown in color. Abdomen membranous and white. Mouth parts attenuated. Basal setae

of tarsal claws not reaching apices of claws. In early stages of development, anal claws

sickle shaped and anal prolegs distinct on the terminal end of abdomen, similar to that of

instar IV. In late stages of development, anal prolegs reduced and not distinct, with anal

claws hook shaped. Abdominal shape changed from wedge shape in early stages to long

barrel shape in later stages. Substantial size added to the abdomen through last instar.

The change in anal prolegs and claws observed in instar IV to V are present in Agraylea

multipunctata Curtis, Oxythira costalis Curtis, and Orthotrichia tetensii Kolbe (Nielsen

1948).

Pupal description

Length 2.3 - 2.4 mm. The mandible blade-shaped, base wide with one long lateral

seta, and with outer margin smooth and inner margin with sawteeth (Fig. 7B). Abdomen

without setae. Two pairs of hook plates present on segments III, IV, and V. Hook plates

in the anterior of abdominal segments slightly larger than posterior ones, and with more

denticles. One pair of anterior hook plates on segments VI and VII. Denticles on anterior

plates ranging from 16 to 20. Anterior hook plates on III each with approximately 18

13

denticles; IV each with 20 denticles; V each with 17 denticles; VI each with 17 denticles;

VII each with 16 denticles. Number of denticles on the posterior hook plates ranging

from 11 to 13. Posterior hook plates on III each with 13 denticles; IV each with 11

denticles; V each with 12 denticles.

Pupal case length 2.6 - 3.4 mm. Curved tube shaped (Fig. 8). Entirely made of

silk. The anterior one-half with much less calcium carbonate deposits than posterior one-

half. Anterior half secreted by pre-pupa.

Female Description

Body length 1.9 to 2.7 mm. Antennae each with 18 segments. Sternum VI with a

posteromesal spine (Fig. 9). The posterior margin of segment VIII ringed with stout

setae. Outer pair of apodemes crossing over inner pair. Inner pair apodemes connecting

with lateral rods of segment IX and extending to the posterior end of segment IX. Outer

pair apodemes extending to posterior of segment VIII. Segment X short, rounded, and

bearing a pair of anterolateral cerci. Bursa copulatrix with a pair of anterior lobes and a

posterior extension around 0.18 jam.

Double lined and curved ventral lobe not described in other May atrichia species.

Posterior extension is about 1.5 as long as anterior body of bursa copulatrix. These

characteristics separate M. ponta from Mayatrichia rualda Mosely (Harris and Holzenthal

1991).

Eggs

Only one incomplete oviposition was observed in light traps. Oviposition

behavior was not observed in the field or lab. The eggs of M. ponta laid in light traps

14

were in a mass contained in a light yellow gelatinous fluid. The diameter of eggs in

female abdomens ranged from 52 to 76 /urn with a mean 65 ^m (n = 8). Eggs of A.

multipunctata, O. costalis, O. tetensii were also contained in a gelatinous mass (Nielsen

1948). However, Dibusa angata laid eggs singly (Resh and Houp 1986).

Larval microhabitat

Larvae of M. ponta were found in stream sections around riffles with well-

oxygenated water. Most inhabited rocks or areas under rock coverage. A few last instar

larvae were found under moss mats beneath fast flowing water and in abandoned blackfly

pupal cases.

Flow readings in front of rocks by Pygmy meter ranged from 19 cm/sec to 75

cm/sec. Currents across microhabitats were compared. Out of six sides of individual

rocks, a one-way ANOVA showed significant difference in flows (n = 10, a = 0.05, p =

0.0001). The bottom was separated as a different group from the other surfaces (Student

Newman Kuels test, a = 0.05). The top surface had the highest mean flow of 32.4 cm/sec

with standard deviation 10.9 cm/sec. The fronts of rocks had the lowest mean flow 20.6

cm/sec with standard deviation 6.9 cm/sec. Analysis of flow regimes showed that early

instars preferred currents between 14 cm/sec and 31 cm/sec. The total numbers of M.

ponta individuals on each rock were negatively correlated with rock surface area (Pearson

Correlation Analysis, r = -0.4424, p = 0.20). This suggests that M. ponta has a slight

tendency to inhabit smaller substrates.

Densities of instar I through IV on the six surfaces of rocks were not significantly

different (n = 10, a = 0.05, p = 0.6838, 0.1721, 0.1892, and 0.31, one-way ANOVA)

15

(Fig. 10). Densities of instar V and pupae were significantly different on six surfaces (a

= 0.05, n = 10, p = 0.0006 and 0.0001 respectively, one-way ANOVA) (Fig. 10).

Populations of instar V and pupae were highest on the bottom of rocks (Student Newman

Kuels tests, a = 0.05).

There are two patterns in microhabitat changes of aquatic insects through

development. First, microhabitat shifts of instars respond to current regimes. Early

instars of M. ponta dispersed more evenly on all surfaces, but last instars preferred the

low-current bottom surface. This was also true in Hydropsyche pellucidulci Curtis (Boon

1979), and H. pellucidula and H. angustipennis Curtis (Muotka 1990). Late instars of

some species have been reported inhabitating high current areas, such as Hydropsyche

betteni Ross (Osborne and Herricks 1987), and Agapetus boulderensis Milne (Poff and

Ward 1992).

Second, some aquatic insects do not change distribution patterns with current

regimes through growth. For example, all instars of Arctopsyche grand is Banks inhabited

every rock surface evenly (Voelz and Ward 1996). Food resources, competition, and

predation play roles in the habitat ontogeny (Werner and Gilliam 1984, Holomuzki and

Short 1990).

The ontogeny of microhabitat has implications for interspecific population

interactions, population ecology, and conservation. To fully understand the patterns of

habitat ontogeny requires exploration of ontogenetic patterns of more species. Further,

laboratory manipulation of flow regime, food resources, competitors, and predators will

help illuminate these mechanisms.

16

Larval case and behavior

Based on series of larvae in the samples and laboratory observations, M. ponta

early instars (I - IV) were free living, and instar V built its case out of silk. As larvae

grew, cases were increased in size by adding silk secretions to the anterior end. Cases

developed toward the anterior end from funnel-shaped to tube-shaped during growth.

The growth of larval cases in other hydroptilids are diverse. O. costalis grew its case in

the posterior direction (Nielsen 1948). Hydroptilafemoralis Eaton, Ithytrichia

lamellaris Eaton and Orthotrichia sp. slit the case and extended the case along the ventral

side (Nielsen 1948). However, most Leucotrichici pictipes re-inhabited old cases

(McAuliffe 1982).

An anal opening on the M. ponta larval case existed in instar V. Feces have been

observed in larval cases. The surface of the M. ponta larval case is covered with a layer

of calcium and magnesium carbonate precipitants. The deposition continues throughout

the life span of instar V and pupal stage. Personal observations and a two-tailed

independent t test indicated pupal cases had thicker precipitation layers (mean thickness

32 |am) than larval cases (mean 13 (am) (df = 10, p = 0.0005). Observations of calcium

carbonate coating have been made on other hydroptilids. The case of M. ponta has a

greater calcium carbonate deposition than cases of other species of Hydroptilidae in

Turner Falls. For example, Neotrichia sp. usually did not have calcium carbonate

precipitation on their cases.

The pre-pupa initially secretes an anterior silk tube and seals the tube with a round

silk cap (Fig. 8). Silk attachment threads radiate to the substrate from the periphery of the

17

opening of the anterior tube. Calcium carbonate precipitants also fasten cases to

substrates. The anterior tube is about the same length as the larval case (Fig. 8). Pre-

pupae seal the anal opening of case. The anterior cover faces outward from the substrate.

The pupa has its head anterior and most of the body is in the anterior tube.

Examination of 13 full larval midguts found that all gut contents were 100 %

unidentifiable detritus. However, larvae have been observed to exhibit green abdomens.

The green larval abdomens suggest that algae is included in the diet.

Emergence and Flight Periodicity

Adults were collected in light traps from April through November (Fig. 12).

Adults were not collected when temperature was less than 8°C. During several days in

February and March, daytime air temperatures increased to 15 and 20° C and adults were

observed, however no adults were caught in light traps. Adults were found in the grass

along shoreline throughout the year.

Emergence behavior was observed in the laboratory. No pupal exuviae

accompanied adults while emerging. Newly emerged adults were soft and white. They

rode in water for a short distance then climbed out of the water onto substrates. Adults

maintained a plastron upon reentering water. This layer of air has been observed during

oviposition of female hydroptilids (Nielsen 1948). The sex ratio of 2,482 adults was

1.43c? : 1?.

Fecundity

Fecundity was estimated by counting eggs from the dissected abdomens of

preserved females. Fecundity did not have a clear trend among different months (Fig.

18

11). The number of eggs of M. ponta per female ranged from 32 to 150 with a mean of

86 and standard deviation of 31. The fecundity of Hydroptilids is not well known.

Fecundity of M. ponta is slightly lower than A. multipunctata, 120-300 eggs, O. costalis,

150-170 eggs, and O. tetensii, 90-210 eggs (Nielsen 1948). Trichoptera having this range

of fecundity anzAgapetus bifidus Curtis, 30-100 eggs (Anderson and Bourne 1974),

Agapetus fuscipes Denning, 12-94 eggs with a mean of 27 eggs, (Anderson 1974), and

Culoptila cantha Ross, 45-120 eggs (Houghton 1996). The fecundity of M. ponta is far

below that of larger trichopterans (Fremling 1960, Wiggins et al. 1980).

Life History and Larval Growth

A multivoltine life history was exhibited by M. ponta, with two summer, a fall,

winter, and spring generations (Fig. 12). Seasonal growth and size distribution of larvae

are shown in Fig. 12. Larvae of M. ponta were found in abundance year round, except

after floods. The slow development of winter generation led to larger body size of

respective larval instars. The winter generations of M. ponta had wider head capsule

width mean 138 /^m (136 - 165 /um) than mean of summer generations 131 fxm (121 - 145

/^m). Correlation of instar occurrence with pupal population and emergence permitted an

interpretation of the life cycle. Cohort asynchrony and generation overlap appeared in the

life cycles. Asynchronous life cycles also appear in other hydroptilids (McAuliffe 1982,

Recasens and Puig 1991, Resh and Houp 1986). Delayed and asynchronous egg hatching

probably contributed to its asynchronous life cycles. The asynchronous egg hatching of

hydroptilids has been observed for H. martini Marshall (Recasens and Puig 1991,

personal communication with Angels Puig). The fast molt rate in early instars and long

19

duration in the last instar caused last instar larvae and pupae to often be more represented

in the population.

A large emergence and high pupae densities were found in my initial samples,

marking the end of a summer generation. I began my sampling too late to define the

beginning of this generation (Fig. 12). Numbers of first and second instars in August

1994 were probably underestimated because a 100 ,um sieve was used. After this date, a

38 jj,m sieve was used.

Decreases in larval and pupal populations were observed at the beginning of

September and again in early November. Floods, sufficient to move rocks, occurred prior

to each of these dates. The travertine stream bed does not provide a hyporheic refuge. It

is thought that during floods most organisms are either physically abraded from rock

surfaces or exposed to currents and catastrophically swept away. Despite air

temperatures suitable for flight activity, reductions in M. ponta emergence were also

noted in samples taken following flood events.

A fall generation began in September, developed to last instar in mid-October, and

emerged in early November. The winter generation started in mid-November, carried

through last instar in January, and began emergence in early March. The prolonged

occurrence of high densities of early instars and low late instar densities suggested slow

development. The asynchronous emergence period of the winter generation was

prolonged through early March, based on high instar V and pupae densities in March.

The end of the winter generation was estimated to be in early March, based on the

following observations. First, despite the fact that adults were not caught in light traps

20

because of low temperature, adult M. ponta were observed in early March. Second, a

sudden increase of early instars densities in mid-March suggested emergence and

oviposition occurred before this date (Fig. 12). Third, the degree days accumulation

based on air temperature reached 1,100 in early March, which is similar to that observed

for a warm season population to complete a life cycle. The relationship between air and

Honey Creek water temperature was significantly correlated (Pearson Correlation analysis

on ranked data, n = 40, r = 0.86, p = 0.0001).

The spring generation started from eggs oviposited in early March and emerged in

late May. The larval development rate increased with rising water temperature. An early

summer generation, developing from May through mid-July, followed the spring

generation. Temperature is recognized as one the most important factors on growth rates

of aquatic insects (Grafius and Anderson 1979, Ward and Stanford 1982, Sweeney 1984).

The long duration of the M. ponta winter generation and shorter generations in warm

seasons are responses to temperature differences. It has been reported that seasonal

temperature changes may also synchronize life cycles (Williams 1991). However, the life

cycles of M. ponta remained asynchronous throughout the study.

The five generations a year of M. ponta is the highest reported for any trichopteran

(Wallace and Anderson 1996). The life histories of hydroptilids were reported as

univoltine in North America (McAuliffe 1982, Resh and Houp 1986). European

hydroptilids have been variously reported as univoltine or multivoltine (Nielsen 1948,

Recasens and Puig 1991). Voltinism variations within the same family are well

recognized. Species of Glossosomatidae (Anderson and Bourne 1974; Georgian and

21

Wallace 1983) and Hydropsychidae (Mackay 1979; Parker and Voshell 1982) have been

reported to have different voltinisms even under the same thermal regime.

APPENDIX

FIGURES

22

23

Figure 1. Location of study area in Honey Creek, Murray County, Oklahoma.

24

25

Figure 2. Water temperature of Honey Creek measured on sampling dates.

26

o 0

27

Figure 3. A plastic-bag flow meter, modified from Gessner(1955). Scale bar = 5 cm.

28

Plastic bag

29

Figure 4. Scatter plot of M. ponta head capsule width against length.

30

l o . 9

O CP

CM 0

! ^ V .

LO T3

31

Figure 5. Instars of M. ponta: A. instar I; B. instar IV. Scale bars = 0.1 mm.

32

ll

33

Figure 6. Instar V of M. ponta: A.. Had (dorsal); B. Thoracic nota (left side); C. Anal claw (lateral ventral side on the top^lX Thoracic legs (right lateral). Scale bars = 0.1 mm.

34

\ /

r "S A s v ^ \ J S ,

y n

ffli

35

Figure 7. Pupa of M. ponta\ A. Iabrum, scale bar = 0.1 mm; B. mandible, scale bar = 0.1 mm; C. abdomen (dorsal), scale bar = 1 mm; D. denticles, scale bar = 0.05 mm.

36

/TV '*i

Ilia nip

iva rv P

Va Vp /fe ,

VI

VII ;?r

37

Figure 8. Pupal case of M. ponta (lateral). Scale bar = 1 mm.

38

39

Figure 9. Female genitalia of M. ponta (ventral): A. terminal abdominal segments; B. bursa copulatrix. Scale bars = 1 mm. Abbreviations: VI-X = abdominal segments VI-X.

40

posterior extension

ventral lobe

anterior lobe

inner rod

41

Figure 10. Plot of instar mean density with standard deviation on different sides of rocks: A.instar I; B. instar II; C. instar III; D. instar IV; E.instar V; F. pupae. ( • indicates statistically different group, SNK, a = 0.05).

42

A. Instar I

12

10

? 8 E 5 6

1 4

f 2 C 0) „ Q 0

-2

-4

I

15 CM <

| 9 10

0

1 5 « c o Q

-5

Top Front Left Right Back Bottom

Sides of rocks

B. Instar II

20

I

Top Front Left Right Back Bottom

Sides of rocks

C. Instar U1

20

_ 15 CM <

s 9 10 5 o S ? 5 '» c o O

-5

" T - r -

I

Top Front Left Right Back Bottom

Sides of rocks

43

D. Instar IV 30

« 20 < E r* ©

g 10

c 4> Q

-10

* ' I l T r

Top Front Left Right Back Bottom

Sides of rocks

E. Instar V

R 10

Top Front Left Right Back Bottom

Sides of rocks

F. Pupae 60

50

04 £ *0 q

3 30 o & ~ 20 W s ° 10

-

i

" - r T - T "I ' T -L -L-

Top Front Left Right Back Bottom

Sides of rocks

44

Figure 11. Fecundity (mean ± 1 S.D.) of M. ponta.

45

No. of Eggs

Jan Apr May Jul Sep Nov

Month

46

Figure 12. Relative abundance of instars and pupae, and adult abundance through August 1994 to August 1995. Width of bars = relative percent of each instar or pupae represented. Each cohort indicates by a curved line and peak oviposition by arrows.

47

to ra

1 0 en

s i j n p v j o - o n

LITERATURE CITED

Anderson, N. H. 1974. The eggs and oviposition behavior of Agapetus fuscipes Curtis

(Trichoptera: Glossosomatidae). Entomol. Mon. Mag. 109: 129-131.

Anderson, N. H., and J. R. Bourne. 1974. Bionomics of three species of three

glossosomatid caddisflies (Trichoptera: Glossosomatidae) in Oregon. Can. J.

Zool. 52:405-411.

Boon, P. J. 1979. Studies on the spatial and temporal distribution of larval

Hydropsychidae in the North Tyne river system (Northern England). Arch.

Hydrobiol. 85: 336-359.

Buikema Jr., A. L., and E. F. Benfield. 1979. Use of macroinvertebrate life history

information in toxicity tests. J. Fish. Res. Board Can. 36: 321-328.

Butler, M. G. 1984. Life histories of aquatic insects, pp. 24-55. In V. H. Resh and D. W.

Rosenberg, [eds.], Ecology of aquatic insects. Prager Scientific Publ., New

York,N.Y.

Clark, D. B., and J. W. Gibson. 1969. Dietary shift in the turtle Pseudemys scripta

Schoepff from youth to maturity. Copeia 1969: 704-706.

Doeg, T., and P. S. Lake. 1981. A technique for assessing the composition and density of

the macroinvertebrate fauna of large stones in streams. Hydrobiologia 80: 3-6.

Fedorenko, A. 1975. Instar and species-specific diets in two species of Chaoborus.

Limnol. Oceanogr. 20: 238-249.

48

49

Frania, H. E. ,and Wiggins, G. B. 1995. Analysis of morphological and behavioural

evidence for the phylogeny and higher classification of Trichoptera. Royal

Ontario Museum, Life Sciences Contributions 160.

Fremling, C. R. 1960. Biology and possible control of nuisance caddisflies of the upper

Mississippi River. Tech. Res. Bull. Iowa State Univ. 483: 856-879.

Georgian, T. J., and J. B. Wallace. 1983. Seasonal production dynamics in a guild of

periphyton-grazing insects in a southern Appalachian stream. Ecology 64: 1236-

1248.

Gessner, F. 1955. Hydrobotanik I. Energiehaushalt. Veb. Deutsch. Ver. Wissensch.,

Berlin. 517 pp.

Goddeeris, B. R. 1987. The time factor in the niche space of Tanytarsus-species in two

ponds in the Belgian Ardennes (Diptera: Chironomidae). Entomol. Scand. Suppl.

29: 281-288.

Grafius, E., and N. H. Anderson. 1979. Population dynamics, bioenergetics, and the role

of Lepidosyoma quercina Ross (Trichoptera: Lepidostomatidae) in an Oregon

woodland stream. Ecology 60: 433-441.

Ham, W.E. 1969. Regional geology of the Arbuckle Mountains, Oklahoma. Okla. Geol.

Survey Guide Book XVIII. 52 pp.

Harris, S. C„ and R. W. Hozenthal. 1991. Hydroptilidae (Trichoptera) of Costa Rica: The

genus Mayatrichia Mosely. J. New York Entomol. Soc. 98: 453-460.

Hennig, W. 1981. Insect phylogeny. John Wiley & Sons, New York. 514 pp.

Houghton, D. C. 1996. Description, life history, and case-building behavior of Culoptila

50

cantha (Ross) (Trichoptera: Glossosomatidae) in the Brazos River, TX. M.S.

thesis. University of North Texas, Denton, Texas.

Holomuzki, J. R. and T. M. Short. 1990. Ontogenetic shifts in habitat use and activity in a

stream-dwelling isopod. Holarct. Ecol. 13:300-307.

Hynes, H. B. N. 1970.The ecology of running waters. University of Toronto Press,

Toronto, Ontario, Canada. 555 pp.

Keast, A. 1977. Mechanisms expanding niche width and minimizing intraspecific

competition in two centrarchid fishes. Evol. Biol. 10: 333-395.

Lehmkuhl, D. M. 1979. Environmental disturbance and life histories: principles and

examples. J. Fish. Res. Board Can. 36: 329-334.

Mackay, R. J. 1979. Life history patterns of some species of Hydropsyche (Trichoptera:

Hydropsychidae) in southern Ontario. Can. J. Zool. 57: 963-975.

Mackay, R. J., and G. B. Wiggins. 1979. Ecological diversity in Trichoptera. Ann. Rev.

Entomol. 24: 185-208.

Martin, N. V. 1966. The significance of food habits in the biology, exploitation, and

management of Algonquin Park, Ontario, lake trout. Trans. Am. Fish. Soc. 95:

415-422.

Martin, T. H., D. M. Johnson, and R. D. Moore. 1991. Fish-mediated alternative life

history strategies in the dragonfly Epitheca cynosura. J. N. Am. Benthol. Soc. 10:

271-279.

McAuliffe, J. R. 1982. Behavior and life history of Leucotrichia pictipes (Banks)

(Trichoptera: Hydroptilidae) with special emphasis on case reoccupancy. Can, J.

51

Zool. 60: 1557-1561.

Minkley, W. L. 1963. The ecology of a spring stream, Doe Run, Meade County,

Kentucky. Wildl. Monogr. 11: 1-124.

Morse, J. C. 1993. A checklist of the Trichoptera of North America, including Greenland

and Mexico. Trans. Am. Entomol. Soc. 119: 47-93.

Mosely, M. E. 1937. Mexican Hydroptilidae (Trichoptera). Trans. R. Entomol. Soc.

Lond. 86: 151-190.

Moulton II, S. R., and K. W. Stewart. 1996. Caddisflies (Trichoptera) of the Interior

Highlands of North America. Mem. Am. Entomol. Institute 56: 1-313.

Moulton, II, S. R., and K. W. Stewart. 1997. A preliminary checklist of Texas

caddisflies (Trichoptera), pp. 349-353. In B. J. Armitage [ed.], Proc. 8th Intl.

Symp. Trichoptera, 9-15 July, 1995, Minneapolis/St. Paul, MN. Ohio Biol.

Survey, Columbus, OH.

Muotka, T. 1990. Coexistence in a guild of filter feeding caddis larvae: do different

instars act as different species? Oecologia 85: 281-292.

Mushinsky, H. R., J. J. Hebrard, and D. S. Vodopich. 1982. Ontogeny of water snake

foraging ecology. Ecology 63: 1624-1629.

Needham, J. G. 1902. A probable new type of hyper-metamorphosis. Psyche 9: 375-

378.

Neill, W. E., and A. Peacock. 1980. Breaking the bottleneck: interactions of invertebrate

predators and nutrients in oligotrophic lakes, pp. 715-724. In W. C. Kerfoot [ed.],

Evolution and ecology of zooplankton communities. University Press of New

52

England, Hanover, N.H.

Nielson, A. 1948. Postembryonic development and biology of the Hydroptilidae. Kgl.

Danske Vidensk. Selsk. Biol. Skr. 5: 1-200.

Oliver, D. R. 1979. Contribution of life history information to taxonomy of aquatic

insects. J. Fish. Res. Board Can. 36: 318-321.

Osborne, L. L., and E. E. Herricks. 1987. Microhabitat characteristics of Hydropsyche

(Trichoptera: Hydropsychidae) and the importance of body size. J. N. Am.

Benthol. Soc. 6: 115-124.

Parker, C. R., and J. R. Voshell, JR. 1982. Life history of some filter-feeding Trichoptera

in Virginia. Can. J. Zool. 60: 1732-1742.

Pianka, E. R. 1976. Competition and niche theory, pp. 114-141. In R. May [ed.],

Theoretical ecology: principles and applications. Saunders, Philadelphia, PA.

Pictet, F. J. 1834. Recherches pour servir l'histoire et l'anatomie des Phryganides.

Geneva. 233 pp.

Poff, N. L., and J. V. Ward. 1992. Heterogeneous currents and algal resources mediate in

situ foraging activity of a mobile stream grazer. Oikos 65: 465-478.

Polis, G. A. 1984. Age structure component of niche width and intraspecific resource

partitioning: can age groups function as ecological species. Am. Natur. 123: 541-

564.

Recasens, L., and M. A. Puig. 1991. Life cycles and growth patterns of Trichoptera in the

Matarrana, a karstic river, pp. 247-251. In C. Tomaszewski [eds.], Proc. 6th Intl.

Symp. Trichoptera, 1989. Adam Mikiewicz University Press, Poznan.

53

Reisen, W. K. 1975. The ecology of Honey Creek: spatial and temporal distribution of

macroinvertebrates. Proc. Okla. Acad. Sci. 55: 25-31.

Reisen, W. K. 1976. The ecology of Honey Creek: temporal patterns of the travertine

periphyton and selected physico-chemical parameters, and the Myriophyllum

community productivity. Proc. Okla. Acad. Sci. 56: 69-74.

Resh, V. H. 1979. Sampling variability and life history features: basic considerations in

the design of aquatic insect studies. J. Fish. Res. Board Can. 36: 290-311.

Resh, V. H., and R. E. Houp. 1986. Life history of the caddisfly Dibusa angata and its

association with red alga Lemanea australis. J. N. Am. Benthol. Soc. 5:28-40.

Ross, H. H. 1944. The caddis flies or Trichoptera of Illinois. Bull. 111. Natur. Hist. Surv.

23(1): 1-326.

SAS Institute. 1991. SAS/STAT guide for personal computers. Version 6 edition. SAS

Institute, Cary NC. 956 pp.

Sweeney, B. W. 1984. Factors influencing life history patterns of aquatic insects, pp. 56-

100. In Resh, V. H. and D. W. Rosenberd, [eds.], The ecology of aquatic insects.

Prager Sci. Publ., New York, NY

Townsend, C. R., and A. G. Hildrew. 1979. Resource partitioning by two freshwater

invertebrate predators with contrasting foraging strategies. J. Anim. Ecol. 48: 909-

920.

Trapp, K. E. 1991. Life history and growth of three populations of Glossosoma nigrior

(Trichoptera: Glossosomatidae) from three thermally distinct locations. Ph.D.

dissertation. Virginia Polytechnic Institute and State University, Blacksburg,

54

Virginia.

Voelz, N. J., and J. V. Ward. 1996. Microdistributions of filter-feeding caddisflies

(Insecta: Trichoptera) in a regulated Rocky Mountain river. Can. J. Zool. 74: 654-

666.

Wallace, J. B. 1975. The larval retreat and food of Arctopsyche with phylogenetic notes

on feeding adaptations in Hydropsychidae Larvae (Trichoptera). Ann. Entomol.

Soc. Am. 68: 167-173.

Wallace, J. B. 1990. Recovery of lotic macroinvertebrate communities from disturbance.

Environ. Manag. 14: 605-620.

Wallace, J. B., and N. H. Anderson. 1996. Habitat, life history, and behavioral

adaptations of aquatic insects, pp. 41-73. In R. W. Merritt and K. W. Cummins

[eds.], An Introduction to the Aquatic Insects of North America. Kendall/Hunt

Publ. Co., Dubuque, IA..

Ward, J. V. 1976. Effects of flow patterns below large dams on stream benthos: a review,

pp. 235-253. In J. F. Osborne and C. H. Allman [eds.], Instream flow needs

symposium, Vol II. American Fisheries Society, Bethesta, MA.

Ward, J. V., and J. A. Stanford. 1982. Thermal responses in the evolutionary ecology of

aquatic insects. Ann. Rev. Entomol. 27: 97-117.

Werner, E. E., and J. F. Gilliam. 1984. The ontogenetic niche and species interactions in

size-structured populations. Ann. Rev. Ecol. Syst. 15: 393-425.

Wells, A. 1985. Larvae and pupae of Australian Hydroptilidae (Trichoptera), with

observations on general biology and relationships. Aust. J. Zool., Suppl. Ser. 113:

55

1-69.

Wells, A. 1992. The first parasitic Trichoptera. Ecol. Entomol. 17: 299-302.

Whitlock, H. N., and J. C. Morse. 1994. Ceraclea enodis, a new species of sponge-

feeding caddisfly (Trichoptera: Leptoceridae) previously misidentified. J. N. Am.

Benthol. Soc.13: 580-591.

Wiggins, G. B. 1990. Systematics of North American Trichoptera: Present status and

future prospect, pp. 203-210. In Kosztarab, M. and C. W. Schaefer [eds.],

Systematics of the North American Insects and Archnids: Status and Needs.

Virginia Polytechnic Institute and State University, Blacksburg, VA.

Wiggins, G. B. 1996a. Larvae of the North American caddisfly genera (Trichoptera).

University of Toronto Press, Toronto, Canada. 457 pp.

Wiggins, G. B. 1996b. Trichoptera Families, pp. 309-349. In R. W. Merritt and K. W.

Cummins [eds.], An Introduction to the Aquatic Insects of North America.

Kendall/Hunt Publ. Co., Dubuque, IA.

Wiggins, G. B., R. J. Mackay, and I. M. Smith. 1980. Evolutionary and ecological

strategies of animals in annual temporary pools. Arch. Hydrobiol./Suppl. 58: 97-

206.

Wiggins, G. B., and W. Wichard. 1989. Phylogeny of pupation in Trichoptera, with

proposal on the origin and higher classification of the order. J. N. Am. Benthol.

Soc. 8: 260-276.

Wilbur, H. M. 1980. Complex life cycles. Ann. Rev. Ecol. Syst. 11: 67-93.

Williams, D. D. 1991. Life history traits of aquatic arthropods in springs. Mem. Ent. Soc.

56

Can. 155: 63-87.

Zar, J. H. 1984. Biostatistical analysis. Prentice-Hall, Englewood Cliffs, NJ. 718 pp.