SICB Logo: Click Here to go to the SICB Home Page

January 3 - Febuary 28, 2021

Meeting Abstract

73-1  Sat Jan 2  Effects of leg loss depend on the leg lost in cockroaches Saintsing, AJ*; Full, RJ; University of California, Berkeley; University of California, Berkeley

Cockroaches are robust to leg loss, but performance may depend on the leg lost. Previously, we discovered that middle leg loss is energetically costly for cockroaches, Blaberus discoidalis, likely because instability forces them to take shorter, faster steps. It is unclear that removal of the front or hind legs would have the same impact. We hypothesized that the loss of hind legs would be energetically costly to cockroaches because greater force might be required to stabilize or drag the unsupported abdomen. We ran cockroaches on a treadmill until they could no longer match the set speed ranging from 30-220 cm/s. Simultaneously, we measured steady-state oxygen consumption, stride frequency, and ground contact time. We collected each measurement for intact individuals, then collected the same measurements after the individual had a single hind leg ablated and then both hind legs removed. We found no significant changes in the rate of oxygen consumption, ground contact time, or stride frequency of individuals after leg loss. Hind leg loss did not significantly lower endurance. However, cockroaches with hind leg loss did adopt a different running strategy compared to intact cockroaches. Cockroaches missing hind legs used an intermittent locomotion strategy with more trials showing brief pauses where they rested their unsupported abdomens. The inability to continuously generate propulsive forces suggests that, while hind leg loss may not increase metabolic cost, it’s consequences likely limit the ability for continuous locomotion. Energetic expenditure cannot fully capture the cost of leg loss.