ZOOLOGY AND ENTOMOLOGY.

Chair: Timothy C. Lockley, USDA APHIS PPQ IFA 

Vicechair: Alex D.W. Acholonu, Alcorn State University 

FRIDAY MORNING

Caribbean Room

9:00 STUDY OF METABOLIC RATES OF GUPPY (POECILIA RETICULATA) AND MOSQUITO-FISH (GAMBUSIA AFFINIS) AT DIFFERENT TEMPERATURES

Tameka L. Ivory and Julius O. Ikenga [*], Mississippi Valley State University, Itta Bena, MS 38941

The metabolic rate of an organism is the sum of complex chemical activities, per unit time, that it must carry out to survive. A segment of these activities, otherwise known as aerobic respiration, occurs in the mitochondria and requires the use of oxygen as the final electron acceptor. We developed this study to compare the metabolic rates (mRs) of guppy (Poecilia reticulata) and mosquitofish (Gambusia affinis) at 23 to 27[degrees]C. Indirect respirometry, which measured the amount of carbon dioxide ([CO.sub.2]) produced, rather than the amount of oxygen consumed by the test fishes, was used to determine the mRs. The mRs were calculated in [micro]M [CO.sub.2] produced by test fishes/ml/hr. The average mRs (7.95, 9.80, 11.0, 12.0, and 14.0 [micro]M CO2/ml/hr) for P. reticulata were found to progressively increase as the temperature (23, 24, 25, 26, and 27[degrees]C) respectively increased. At the same temperatures above, however, the average mRs so far collected for G. affinis (11.3, 11.0, 12.6, 14.0, and 12 .5 [micro][micro]M CO2/ml/hr) failed to show any similar progressive increase. P. reticulata that were one half the weight of G. affinis had mRs of 9.00, 12.0, and 28.5 [micro]M [CO.sub.2]/ml/hr at 23, 26, and 27[degrees]C, respectively. Comparatively, the G. affinis that were twice the weight of P. reticulata had mRs of 11.5, 11.6, and 17.3 [micro]M [CO.sub.2]/ml/hr at 23, 26, and 27[degrees]C, respectively.

9:15 THE ABILITY OF DRAGONFLY LARVAE TO GRAB A SPECIFIC LOCATION ON A PREY'S BODY

Marty L. Harvill [*] and Robert M. Kobza, Mississippi University for Women, Columbus, MS 39701 and Florida International University Miami, FL 33199

The main objective of this study was to determine if Aeschna dragonfly larvae randomly grab a prey or target a specific area on the prey's body. The study was conducted in a partitioned holding/observation chamber (38 L) using 14 Aeschna dragonfly larvae (3rd and 4th instar) and 50 (11-25 mm) Gambusia fish. The water temperature was maintained at 22[degrees]C and during observations the light level was turned down to 0.0145 lux. Dragonfly larvae were starved for two days before eight larvae and 12-15 Gambusia were placed into the observation chamber. Each of 45 captures of fish by dragonflies were video taped and measurements taken of the total length of fish (mm) and grab location to the tip of the mouth (mm). We examined the distribution of grab location/total length of fish ratios and found the targeted grab location was location specific which indicated a nonrandom grab. This study allows us to better understand the optic ability and natural selection on these ambush predators.

9:30 VARIABILITY IN FEEDING AND SEARCHING BEHAVIOR OF FIELD COLLECTED POPULATIONS OF FRUIT FLIES (DROSOPHILA MELANOGASTER)

Jimena M. Aracena [*] and Rebecca Rogers, Mississippi University for Women, Columbus MS 39701

Populations of Drosophila melanogaster were collected in the field near Columbus, MS. Isofemale lines derived from the field collections were tested in the laboratory on patches of sucrose solutions. We found variability in feeding thresholds, search behavior on patches of food, and survival during food deprivation between the populations tested. Because these traits are crucial to survival and also have been demonstrated to be heritable, they are subject to natural selection. We propose this pilot study as a model for laboratory selection and eventual characterization of behavioral heritable traits.

9:45 THE ANACRONEURIA GUAMBIANA COMPLEX OF SOUTH AMERICA (PLECOPTERA: PERLIDAE)

Bill P. Stark [*] and Maria del Carmen Zuniga, Mississippi College, Clinton, MS 39058 and Universidad del Valle, Cali, Colombia

Anacroneuria is a large, neotropical stonefly genus with over 200 nominal species found from Argentina to Arizona. Most species are known from their original descriptions and there has been little effort made to understand phylogenetic relationships within this diverse assemblage. In this study we formally define the Anacroneuria guambiana group and recognize A. chorerra Stark (Venezuela), A. guambiana Zuniga & Stark (Colombia), A. pacifica Rojas & Baena (Colombia), A. regleta Stark & Rojas (Colombia), A. sacapa Stark & Zuniga (Colombia), and A. uru Stark & Sivec (Peru) as members of the complex. A preliminary phylogeny of the group is proposed based on characters extracted from variations in male aedeagal morphology.

10:00 Break

10:15 CHARACTERISTICS AND TOXICITY OF THE DRINKING WATER DISINFECTION BY-PRODUCT 3-CHLORO-4-(DICHLOROMETHYL)-5-HYDROXY-2[5H]-FURANONE (MX) TO MEDAKA (ORYZIAS LATIPES)

David R. Geter [*][*], William E. Hawkins [1], and John W. Fournie [2], (1.)Gulf Coast Research Laboratory, University of Southern Mississippi, Ocean Springs, MS 39564 and (2.)U.S. Environmental Protection Agency, Gulf Breeze, FL 32561

The compound 3-chloro-4-(dichloromethyl)-5hydroxy-2(5H)-furanone, also known as MX, is a byproduct of wood pulp manufacture and a contaminant of chlorinated drinking and sewage water. MX has recently been shown to be carcinogenic to rodents. However, no data exist for its effects on fish. We investigated the acute toxicity of MX in a 48-hour LC50 static exposure using Japanese medaka (Oryzias latipes) fry. Ten-day-old medaka were exposed to MX concentrations of 0, 25, 50, 100 and 200 mg/L. Calculations using the moving average and binomial methods gave an approximate 48-hour LC5O of 138 and 128 mg/L, respectively. The MX in solution decreased an average of 15% in 48 hours across all test concentrations with a half-life of 120 hours. Concentrations of MX found in environmental and drinking waters (normally in the lower parts per billion) are far below that found to be toxic to medaka in this study. Nevertheless, these data help establish exposure conditions that will allow us to investigate mechanisms of MX ef fects on fish, especially studies designed to determine the carcinogenicity of MX.

10:30 INTERSPECIFIC DIFFERENCES IN SAGITTAE OF CYNOSCION(TELEOSTEI: SCIAENIDAE)

Windsor E. Aguirre, Gulf Coast Research Laboratory, Ocean Springs, MS 39566

Length and height of sagittae (saccular otoliths) were measured in nine species of the genus Cynoscion (Teleostei: Sciaenidae), four from the western Atlantic and five from the eastern Pacific. Compared to other American sciaenids, sagittae of Cynoscion are relatively large and elongate. In all species of Cynoscion examined, sagitta length grows at a faster rate than sagitta height. As a consequence, sagittae become relatively longer as the fish get larger. However, slopes for both sagitta length and height decrease as standard length increases, with sagittae becoming smaller relative to the overall size of the fish. Differences in sagitta shape and size exist among the species examined. Sagittae of C. nothus are of greater height than those of the other species, appearing rounder in shape. Sagittae of C. arenarius, C. regalis, and C. squamipinnis are relatively large and elongate, and very similar to one another. Sagittae of C. nebulosus are of slightly less length and height than those of the above mention ed species. Sagittae of C. albus, C. analis, C. phoxocephalus, and C. xanthulus, tend to be smaller than those of the other species. The reasons for these differences are not clear. However, sagittae are useful for distinguishing among morphologically similar species within Cynoscion and may contribute to the understanding of phylogenetic relationships.

10:45 ARE OMEGA-3 FATTY ACIDS A CRUCIAL LIPID STORE IN DESICCATION RESISTANT DORMANT EGGS OF THE TEMPORARY POND COPEPOD AGLAODIAPTOMUS STAGNALIS FORBES?

Judith L. Williams [*] and Patricia M. Biesiot, University of Southern Mississippi Gulf Coast, Long Beach, MS 39560 and University of Southern Mississippi, Hattiesburg, MS 39406

Lipids are important reserves of energy for developing as well as dormant organisms. Marine copepods store tremendous amounts of wax esters and triacylglycerols (TAG) prior to dormancy in oceanic environments. Marine copepods also have unusually large amounts of omega-3 fatty acids. These fatty acids are crucial for normal development and physiologicffl function of all animals; for that reason they are often called essential fatty acids (EFA). The temporary pond copepod Aglaodiaptomus stagnalis produces and releases large, desiccant resistant dormant eggs on an annual basis. These eggs accumulate large amounts of both TAG and fatty acids prior to dormancy. Our preliminary data show that females with egg sacs have higher body accumulation of certain EFAs (the same as those shown to be critical in fish and invertebrate development) than those without eggs. This suggests that the females may shunt these vitally important fatty acids into the eggs, thus providing necessary precursors for rapid development follow ing cessation of dormancy.

11:00 WATER QUALITY STUDIES ON THE BIG SUNFLOWER RIVER, MISSISSIPPI

Alex D.W. Acholonu, Gayle Culley [*], Yalonda Grant, and Ketia Shumaker, Alcorn State University, Alcorn State, MS 39096

The Mississippi Department of Environmental Quality has set regulations to protect water quality. Water quality standards were adopted by the State in 1995 for interstate, intrastate, and coastal waters. The policy was adopted to protect and upgrade lotic(running) water quality within the State. This study was therefore conducted to find out if the Big Sunflower River meets the standard of fresh water bodies in Mississippi. Adverse water quality is usually indicated by such conditions as increased concentrations of metals and nutrients, decreased dissolved oxygen, and diverse changes in physical characteristics. During the period September to October 1999, water samples were collected at different locations in three replicates from the Big Sunflower River in the area near the Delta National Forest in Sharkey County. This area is about 51 miles north of Vicksburg. The samples were collected, taken to the laboratory, and analyzed according to standard methods. Of the many parameters tested: viz., surface water temperature, hardness, alkalinity, pH, nitrate, zinc, dissolved oxygen, copper, chromate, phosphate, chlorine, and fluorine, the following were recorded: hardness, alkalinity, pH, dissolved oxygen, chromate, chlorine, and fluorine. The average surface water temperature was 24.30[degrees]C. This is a preliminary report. The study is still in progress. But based on the results so far obtained, the Big Sunflower River appears to be polluted, at least, at the areas surveyed.

11:15 ANALYSIS OF BED SEDIMENTS OF THE BIG SUNFLOWER RIVER IN MISSISSIPPI FOR POLYCYCLIC AROMATIC HYDROCARBONS

Alex D.W. Acholonu [1], Arther T. Gates [1][*], Keturah Morris [1], and K.T. Valsaraj [2], (1.) Alcorn State University, Alcorn State, MS 39096 and (2.) Louisiana State University, Baton Rouge, LA

Acholonu et al. (1997) conducted a study on benthic invetebrates and their substrates at Lake Yazoo and the Yazoo River. This study revealed the presence of three different kinds of polycyclic aromatic hydrocarbons (PAHs) which are polutants, namely; pyrene, chrysene, and dibenzo(a,h)-anthracene. A similiar study was recently initiated at the Big Sunflower River, a tributary of the Yazoo River. Between the months of May and October 1999, bed sediment samples were collected from different sites in three replicates from the Big Sunflower River in the area in close proximity to the Delta National Forest in Sharkey County. The area is about 51 miles north of Vicksburg. The samples were collected about 50 meters apart using the Ekman grab and/or a Ponar grab and occasionally by scraping the bottom with a plastic pale in shallow areas. The samples were put in pales, taken to the laboratory and refrigerated until chemically analyzed. The sediments were extracted using EPA-SW 846 method 3550B (ultrasonic extraction) and cleanup performed using EPA-SW Method 3630C (Silica Gel Cleanup).The extracts were analyzed using HPLC (gradient method). The following PAHs were detected in all sites: benzo(a)pyrene, phenanthrene, fluoranthene, pyrene, and chrysene. This is a preliminary report as the study is still in progress. Based on the results obtained so far, the Big Sunflower River is polluted at least in the areas studied.

11:30 Divisional Business Meeting

11:45 Divisional Poster Session

MORPHOLOGICAL AND BEHAVIORAL DIFFERENCES OF THE COMMON ORCHARD SPIDER, LICAUGE VENUSTE, IN RELATION TO DIFFERENT FOREST MANAGEMENT PRACTICES

Melodie Sheri Millsaps, Mississippi University for Women, Columbus, MS 39701

The purpose of this study was to determine how forest management practices effect orchard spiders. In previous research, it was noted that the orchard spiders living in different habitats and forest management areas showed signs of slight morphological and behavioral differences. To determine exactly how the surrounding environment had effected this spider, spot maps were collected noting the habitat and forest management area these spiders were found in. A check list was also devised for each spider found that checked for leg color, web height, community occurrences, and abdomen size. During the study it was recorded that these spiders sometimes live in communities with spiders of a different species, also. Analysis of the data concluded that the orchard spider still has the densest population and moist, low-lying areas on uneven-aged forest management. 59.5 % of the sample spiders had metallic legs and the average abdomen size of these spiders is 2.5 mm. Data analysis also indicated that 97.88% of the spid ers build there webs below 1 m, 58.38% of these spiders live in web communities, and 24.87% of those spiders lived in communities with different species. It was concluded that successful orchard spiders have metallic legs, webs below 1 m, 2.5 mm abdomens, and normally live in communities. It is not that beneficial, however, for orchard spiders to form communities with different species.