Russell Burke
Below you can find examples of the types of projects undergraduates have done in my lab, in no particular order. We have a pretty good history of publishing these projects in referred, scientific journals. Students are included as authors if they help work on the publication.
Sexual Dimorphism and Reproductive Cycles in Podarcis sicula John Corso
Abstract: Sexual dimorphism with regard to body size and other morphological characteristics in P. siculaand seasonal changes in gonadal and fat body sizes in relation to the timing of reproductive events were investigated. Sexual dimorphism, with males being larger than females is caused by for sexual selection. Males have (relative to body length) significantly longer fore- and hind-limbs and both a longer and wider head. Development of testes and epididymis were synchronous; maximum size was reached during May-July and was followed by a period of regression until early autumn. Follicle and oviduct diameters were largest in females between May and July. Larger females produced larger clutches than smaller females. The frequency of females simultaneous containingyolked follicles, ovarian eggs and corpus luteum in May-July was 37%. Second clutches, however, were not noted. Fat body sizes coupled the breeding season. Male breeding and courtship rituals and spermatogenesis and female vitellogenesis and oogenesis employed lipid stores.
Food habits of a New York population of Italian wall lizards, Podarcis sicula (Reptilia, Lacertidae) Nirev Patel
Abstract: I assessed European wall lizards, Podarcis sicula collected from populations introduced to the U.S., for the ability to tolerate freezing temperatures. This has implications for the future of this species currently undergoing rapid range expansion, and allows us to make informed guesses about its over-wintering behavior. I first determined that they could regularly survive supercooling down to -5oC (temperature monitored by thermocouple) for at least 60 minutes. Next, individuals were cooled to -5 oC and freezing was induced. I thawed these lizards after 15 minutes and held them at +5o for 24 hours, when they were checked again for life signs. All lizards frozen in this fashion died. Thus when internal ice formation was initiated as would be expected in a natural environment, they rapidly froze and died. This species does not appear to be freeze tolerant, which differs from results reported by Claussen et al. for a conspecific (P. muralis). I demonstrated that our different results are very likely due to a difference in experimental technique. Standardization of techniques and definitions are needed if freeze tolerance comparisons are to be made between species and populations.
Freeze tolerance and supercooling ability in the Italian wall lizard, Podarcis sicula, introduced to Long Island NY. Ahmed A. Hussain
Abstract: I studied the food habits of Italian ruin lizards, Podarcis sicula, introduced to Long Island New York 34 years ago. We recovered 436 prey items from 96 lizards. There was no significant relationship between the percentage of lizards without any prey items and date of capture. Diets of males and females differ in the number of prey items per lizard, overall prey diversity and prey evenness, suggesting important differences in foraging habits. I found remarkably high similarity between species diversity values for the Long Island and two European populations. There was no correlation between prey size and either head width or snout-vent length.
The Ecological Impacts of Artemisia vulgaris and Lespedeza cuneata on the Hempstead Plains Brie-Anne McKernan and Christine Kutzman
Abstract: The Hempstead Plains, a tall-grass community in Uniondale, NY, dramatically exhibits the effects of a non-native plant invasion by Artemisia vulgaris (common mugwort) and Lespedeza cuneata. We evaluated some of the ecological impacts of these plants in a 1.72 hectare study site in the Hempstead Plains. The density of A. vulgaris plants was found to have decreased overall over a four-year time interval, which is most likely due to systematic over-estimations of percent coverage in 1995. The several foot paths present in the Plains do not appear to be routes for A. vulgaris’s dispersal. Instead, the increased densities present in plots near the north and south boarders suggest that A. vulgaris is utilizing adventitious runners to gradually colonize the Plains from external areas. Soil nutrient experiments revealed significant pH increases in soil samples removed directly from the Plains and also in controlled growth experiments. The increase in pH may alter the abundance of essential chemical forms of soil nutrients and minerals and thereby decrease the ability of native plant species to compete. We determined that there was an overall decrease in L. cuneata density, but suspect this apparent decrease is due to errors in the earlier data. There was a significant increase in L. cuneata densities along the perimeter of the study area, which may be due to spread from the surrounding environment. There were also high densities on the paths, which could be due to disturbance. Our greenhouse experiments showed L. cuneata grows by increasing branch number rather than height, but it does increase in weight. Soil analyses showed that L. cuneata has no effect on % moisture or organic matter composition, but it did cause total nitrogen to decrease. This was not expected because L. cuneata is a legume, which typically fix nitrogen. The most significant difference was a large increase in soil pH.
Comparing the number of terrapin nests on Ruler’s Bar Hassock 1999-2002 Alison Swendenberg
Feinberg counted predated 1822 terrapin nests on the island of Ruler’s Bar Hassock in 1999, and observed three clear peaks of nesting activity over the nesting season, which began 3 June and ended 23 July. This work had not been repeated to obtain a measure of inter-annual variability. I followed the same procedure as Feinberg in the spring summer of 2002, making weekly surveys of terrapin nesting habitat over the areas of Ruler’s Bar Hassock used by nesting terrapins. I counted 1837 predated nests. In 2002 nesting started on 1 June and lasted until 10 August. No peaks of nesting activity were noted.
The Importance of Raccoon Feces to the Nest Counts of the Diamondback Terrapin at Jamaica Bay Wildlife Refuge Susan Felice
Feinberg (2000) noted differences in the pattern of raccoon predation on terrapin nests over the nesting season. In June, the raccoons consumed only egg contents and left eggshells behind in a pile. In July, raccoons consumed the entire egg, and eggshells were found commonly in raccoon feces. This is important to the terrapin nest counts. If there are no eggshells present at the site of a hole that might be a nest, then it is usually not counted as a nest. We are then recording lower counts of terrapin nests then there actually are. My goal was to determine whether this was a recurrent pattern and quantify this pattern.
Samples of raccoon feces were collected weekly throughout the months of June and July of 2002. The samples were dried, weighed, and ashed. The ashed fecal samples were digested in acid into solution and calcium analysis through EDTA titration was performed to calculate the percent of eggshells present in each fecal sample.
Observational results show there is in fact a mid-seasonal shift in consumption of the eggs and eggshells. The calcium analysis through EDTA titration supported this conclusion. With the calcium analysis results, we will now be able to adjust the counts of terrapin nests laid to a more accurate reading.
