Impacto da autotomia no desenvolvimento da aranha Vectius niger (Trochanteriidae): uma abordagem experimental

Abstract

Autotomy, the voluntary shedding of body appendages, is an important adaptive strategy in several animal groups, particularly arthropods, providing benefits such as predator escape and increased survival. However, this mechanism may also impose costs related to development, locomotion, and resource acquisition. This study aimed to evaluate the effects of autotomy on the development of the spider Vectius niger Simon, 1880 (Araneae: Trochanteriidae) by investigating the impact of limb loss on body growth and food consumption. Considering that autotomy may impose physiological costs associated with wound healing, regeneration, and energy reallocation, we hypothesized that (i) individuals subjected to autotomy would exhibit reduced absolute cephalothorax growth, (ii) autotomized spiders would show greater total prey consumption than non-autotomized individuals, and (iii) autotomized spiders would exhibit higher mean prey consumption per instar than control individuals. Specimens collected from Caesalpinia pluviosa (DC., 1825) (Fabaceae:Caesalpinioideae) were maintained under laboratory conditions and assigned to four experimental groups: induced autotomy, spontaneous autotomy, induced plus spontaneous autotomy, and a control group. The results showed that autotomy had no significant effect on body growth or prey consumption per instar. In contrast, spiders subjected to induced autotomy, either alone or combined with spontaneous autotomy, exhibited a significant reduction in total food consumption compared with the control group. These findings refute the energetic compensation hypothesis, as limb loss did not increase food intake to offset the energetic costs of regeneration. Instead, they suggest that the costs of autotomy are more closely associated with reduced foraging activity and the physiological demands of tissue regeneration than with direct constraints on somatic growth. Overall, the results suggest that Vectius niger may be capable of maintaining normal development despite limb loss, although with significant alterations in feeding patterns, thereby contributing to a better understanding of the ecological and physiological consequences of autotomy in spiders.