%0 Journal Article %J Journal of Ethology %D 2009 %T Discrimination of chemical stimuli in conspecific fecal pellets by a visually adept iguanid lizard, Crotaphytus collaris %A Wilgers, D.J. %A Horne, E.A. %K Chemoreception %K Gular pump %K Olfaction %K Tongue-flick %K Vomerolfaction %X

Iguanid lizards are known for visual acuity and a diminished vomeronasal organ, which has led to mixed conclusions on whether iguanids use chemical cues. The collared lizard, Crotaphytus collaris, is a territorial iguanid that lives in open rocky habitats. Fecal pellets placed prominently on open rocky perches may provide an ideal mechanism for intraspecific chemical signaling. In order to determine whether collared lizards can discriminate between chemical stimuli found in conspecific fecal pellets, we collected 24 males and 25 females to analyze sex-specific behavioral responses via tongue-flicks and a newly observed behavior for the species, gular pumps, to cotton swabs containing water, cologne, chemical stimuli from conspecific male and female fecal pellets, and the lizard’s own fecal pellet. Both sexes were able to discriminate chemical stimuli from water via at least one behavior. Male collared lizards exhibited greater rates of response (tongue-flick and gular pumps) toward male fecal pellets when compared to the negative water control. Our results also suggest individuals may be able to discriminate between fecal pellets, as indicated by generally greater (but non-significant) counts of male tongue-flick responses to male fecal pellets when compared to their own. Collared lizard chemical discrimination appears to utilize tongue-flick and gular pump behaviors, possibly associated with distinct chemosensory modes (vomerolfaction and olfaction). Based on this study, we suggest that chemical signals may play a greater role in intraspecific communication than previously thought in this highly visual lizard.

%B Journal of Ethology %V 27 %P 157 -163 %G eng %U https://link.springer.com/article/10.1007%2Fs10164-008-0100-5 %M KNZ001247 %R 10.1007/s10164-008-0100-5 %0 Journal Article %J Southwestern Naturalist %D 2007 %T Spatial variation in predation attempts on artificial snakes in a fire-disturbed tallgrass prairie %A Wilgers, D.J. %A Horne, E.A. %X The tallgrass prairie historically burned every 2 to 3 y, removing the litter layer and leaving post-burn environments inhospitable to many terrestrial species. Selection pressures, such as lack of food and shelter and increased predation, are intensified for some species over limited time periods. To quantify predation pressures on large snakes, artificial snakes were placed in recently burned and long-term unburned areas of a grassland system in northeastern Kansas. Any disturbance to the original placement of the model snake was considered a predation attempt. Statistical models were used to estimate daily survival rates of individual artificial snakes within both habitat types. A group effect (burned vs. unburned) was selected as the single top model, garnishing >93% of the support for the data. Survival estimates from this top model indicated artificial snakes in newly burned areas had significantly lower daily survival than those placed within unburned sites. Indirect evidence from destroyed artificial snakes indicated raptors were a major predator on large snakes. Overall herpetofaunal activity in burned areas was low during the first 20 d post-burn, with increasing activity throughout the rest of the season. However, activity within unburned areas was constant throughout the spring. Burning tallgrass prairie likely increases predation pressure on large snakes in the area for 1 to 2 mo following the burn due to the lack of cover against aerial predators. %B Southwestern Naturalist %V 52 %P 263 -270 %G eng %M KNZ001084 %R 10.1894/0038-4909(2007)52[263:SVIPAO]2.0.CO;2 %0 Journal Article %J Journal of Herpetology %D 2006 %T Effects of burn regimes ontallgrass prairie herpetofaunal species diversity and communitycomposition in the Flint Hills, Kansas %A Wilgers, D.J. %A Horne, E.A. %X The Flint Hills region of Kansas is the largest contiguous area of tallgrass prairie remaining today. Historically, the tallgrass prairie burned every 2–3 yr on average, but current land managers have altered burn regimes, resulting in a range of habitats from annually burned to long-term unburned. We used drift fence/funnel trap arrays and coverboards to estimate species richness, evenness, and diversity of herpetofauna within three different burn regimes: annual, 4-yr, and long-term unburned at Konza Prairie Biological Station, Riley County, Kansas. During the spring and fall of 2003–2004, 315 individuals from 20 species were captured across all burn regimes. Herpetofaunal species richness, evenness, and diversity estimates were not different between the three burn treatments. However, because of species-specific responses to individual burn regimes, community composition was significantly different between the habitats (χ2 = 158.19, df = 20, P < 0.001). Four species exhibited preferences among burn regimes, which differed significantly from independent assortment, with Eumeces obsoletus and Phrynosoma cornutum preferring annual burn treatments, Scincella lateralis preferring 4-yr burn treatments, and Diadophis punctatus preferring long-term unburned treatments. Species-specific responses were likely because of changes in vegetation structure and microhabitat (temperature and moisture content) created through different frequencies of fire disturbances. Maximizing large-scale herpetofaunal diversity across the Flint Hills' rangelands could be accomplished by creating a large number of small scale habitat types through a mosaic style burning plan. %B Journal of Herpetology %V 40 %P 49 -60 %G eng %M KNZ001030 %R 10.1670/162-05A.1 %0 Journal Article %J Herpetologica %D 2006 %T Effects of rangeland management on community dynamics of the herpetofauna of the tallgrass prairie %A Wilgers, D.J. %A Horne, E.A. %A Sandercock, B.K. %A Volkmann, A.W. %K Amphibians %K Flint Hills %K Mark-recapture %K POPAN %K Reptiles %K Species loss %X The Flint Hills of Kansas and Oklahoma are the largest remaining tracts of tallgrass prairie in North America. This area has undergone major changes in land management practices in the past 30 years. Traditional season-long cattle stocking with variable burn schedules has diversified to include intensive-early cattle stocking accompanied by annual burning. To understand how different land management practices affect the herpetofauna of a tallgrass prairie, we used mark-recapture statistics to analyze herpetofaunal community dynamics. We analyzed survey data collected over a 15-year time span (1989–2003) from a rangeland site in Cowley County, KS, USA. A modified Jolly-Seber open population model, POPAN-5, was used to estimate four community parameters: probability of species loss (φ′), probability of detection (P), probability of entry (Pent), and species richness (N). The top models included burn status as a covariate for species loss rate, while cattle stocking received moderate support as a covariate. Rates of species loss were higher during burn years (φ′  =  0.04, 95% CI: 0.02 to 0.08) than nonburn years (φ′  =  0.00, 95% CI: 0.00 to 0.01). Analysis of the impacts of different management practices was difficult due to confounding effects of changes in both burning and grazing. Declines in species richness tended to be steepest during a period of season-long stocking, but results were not statistically significant. Though our limited data set does not allow us to draw strong conclusions on the effects of land management on herpetofaunal populations, the mark-recapture models illustrated in our study should prove to be a valuable tool in future analyses of similar data. %B Herpetologica %V 62 %P 378 -388 %G eng %M KNZ001079 %R 10.1655/0018-0831(2006)62[378:EORMOC]2.0.CO;2 %0 Thesis %D 2005 %T Impacts of land management practices on tallgrassprairie herpetofauna %A Wilgers, D.J. %I Kansas State University %C Manhattan, KS %V MS Thesis %P 1 -105 %G eng %9 M.S. Thesis %M KNZ001004