Previous studies have found that weather conditions play a significant role as environmental cues for the timing of nesting in a variety of herpetofauna. Precipitation and cloud cover are two environmental factors that potentially act as cues and impact diamondback terrapin (Malaclemys terrapin) nesting behavior. In this study, we observed the nesting population of diamondback terrapins on the Wallops Island Flight Facility in Wallops Island, Virginia. In addition to a mark-recapture population study, capture date and time was also recorded and compared against daily precipitation measurements and hourly cloud cover data to observe any patterns in frequency distribution. We hypothesized that both cloud cover and precipitation were environmental cues for nesting females, and that precipitation would precede an increase in nesting, and a decrease in cloud cover would correlate to an immediate increase in nesting. Studies done in the past have supported the predictions that terrapins prefer clear skies and wet conditions due to recent rainfall.
Results/Conclusions
We found that of the terrapins with capture time data attached to them (n = 299), there was a statistically significant preference for mostly cloudy or overcast conditions (χ2= 69.84, p < 0.05). In addition, we found that terrapins observed nesting over the five study (n = 306) preferred days with less than 1.27 mm of precipitation (χ2= 128.12, p < 0.05). These results contradict findings from previous studies; however, those studies were conducted in other geographic areas within the range of the diamondback terrapin. It is possible that selective pressures on this population have resulted in terrapins using other environmental cues in selecting the timing of nesting. A preference for mostly cloudy conditions may be useful to reduce heat stress and risk of desiccation or alternatively that cloudy and overcast conditions simply correlate with other factors (e.g. barometric pressure or predation pressure) that were not considered in this study.