Influence of environmental factors on longevity of the brown recluse spider.

Abstract

Field-collected adults of Loxosceles reclusa were examined for weight loss, longevity, and body water content at death under the influence of food, water, sex, RH, ambient water vapor pressure, vapor pressure deficit, and temperature. Data were statistically analyzed and fitted with models. The amount of water left in the body at the time of death was independent of environmental factors, consisting of 28.77–42.68% of the original body weight. The natural logarithm of longevity varied linearly with vapor pressure, but temperature had a nonlinear effect. Spiders engorged in the field prior to tests generally survived longer (124–222 days) than those field-collected, starved, and subsequently fed on water (55–94 days). Percentage weight loss per day was exponentially related to longevity and was influenced primarily by temperature and vapor pressure deficit. Original weight, RH, and sex did not significantly influence longevity, weight loss, or the amount of body water content at death. Physiological adaptations of the spider to its natural habitat are discussed with reference to its water relations.