Leg Loss and Fitness in Female Green Lynx Spiders Peucetia viridans
Mentor:Martina Ramirez, Professor of Biology, Loyola Marymount University
Autotomy is the loss of a grabbed or blocked appendage by reflex, which can be followed in some species by the regeneration of the lost limb. Autotomy allows an individual to escape from predators, to flee from a conspecific, or to release itself from the exuviae during a faulty molt. The loss of a leg is also a handicap, since it can result in a decrease in mobility, as well as reduced functionality in specific behaviors. Leg loss and its consequences has often been studied in male spiders but not in females. Thus, the purpose of this study was to assess the impact of leg loss on reproductive output in female green lynx spiders Peucetia viridans, by comparing output indices for spiders with different numbers of missing legs. From 2004-2007 and in 2010-2011, 834 field-collected adult female P. viridans and their egg sacs were gathered from multiple sites in southern California. In lab, I recorded the number and position of missing legs for each female, as well as egg sac mass (mg), egg number, and mean sac mass per egg (mg). Analysis of variance (ANOVA) was conducted to compare reproductive output for females with different levels of leg loss. Overall, I have found that females missing one or two legs significantly underperformed females with no leg loss and females missing three or more legs in terms of egg sac weight (p = 0.0006) and egg number (p = 0.0008). These findings suggest that leg loss in spiders has negative consequences for females in terms of reduced reproductive performance. The odd upward spike in egg sac weight and egg number for females missing three or more legs may be due to peculiarities in the data for these 13 spiders, something I am currently investigating.