Meeting Abstract
Many animals voluntarily release their legs and/or other appendages during encounters with potential predators. Many life-history traits may influence which body parts are lost. However, comprehensive surveys of such traits in the field are rare. We aimed to describe the frequency of leg loss in 16 species from 6 genera of Scleresomatidae daddy long-legs (Arachnida: Opiliones) across the Americas, as well as elucidate potential morphological, behavioral and ecological factors affecting the patterns of leg loss (autotomy). Across species, the percentage of autotomized individuals was generally high but variable with some populations showing autotomy rates of up to 60%. In general, species from temperate zones showed lower autotomy rates. We suggest that this pattern is explained by higher predation pressure in tropical regions. Among sexes we also found different patterns of leg loss even among the same genera, potentially associated with life history differences between species. In one species of Prionostemma from Costa Rica females were larger than males, and their legs were longer, with an interesting exception: the length of the antenniform legs (the second pair) did not differ between sexes. Males having longer legs could be related with finding food and mates more efficiently, and even for courtship behavior purposes. However, this idea remains untested. Finally, we found differences in the patterns loss between leg types. We found that the second pair of legs were lost three times more frequently than expected by chance in all 16 species, possibly due to its longer length and/or behaviors associated with exploration as these arachnids use legs II as sensory organs to probe the environment.
