Feeding behavior and social interactions of the Argentine ant Linepithema humile change with sucrose concentration

Abstract

Liquid sugar baits are well accepted by the Argentine ant Linepithema humile and are suitable for the chemical control of this invasive species. We evaluated how sugar concentrations affect the foraging behavior of L. humile individuals. We quantified feeding variables for individual foragers (ingested load, feeding time and solution intake rate) when feeding on sucrose solutions of different concentrations, as well as post-feeding interactions with nestmates. Solutions of intermediate sucrose concentrations (10–30%) were the most consumed and had the highest intake rates, whereas solutions of high sucrose concentrations (60 and 70%) resulted in extended feeding times, low intake rates and ants having smaller crop loads. In terms of post-feeding interactions, individuals fed solutions of intermediate sucrose concentrations (20%) had the highest probability of conducting trophallaxis and the smallest latency to drop exposure (i.e. lowest time delay). Trophallaxis duration increased with increasing sucrose concentrations. Behavioral motor displays, including contacts with head jerking and walking with a gaster waggle, were lowest for individuals that ingested the more dilute sucrose solution (5%). These behaviors have been previously suggested to act as a communication channel for the activation and/or recruitment of nestmates. We show here that sucrose concentration affects feeding dynamics and modulates decision making related to individual behavior and social interactions of foragers. Our results indicate that intermediate sucrose concentrations (ca. 20%), appear to be most appropriate for toxic baits because they promote rapid foraging cycles, a high crop load per individual, and a high degree of stimulation for recruitment.

Laboratory and field insights into the dynamics and behavior of Argentine ants, Linepithema humile, feeding from hydrogels

“…Ingestion volume from hydrogels decreased as sucrose concentration increased, consistent with results of L. humile and other ant species feeding from liquid droplets. 18,23,24 However, ants spent less time feeding from hydrogels with increasing sucrose concentration. This was unexpected because when feeding from liquid droplets, L. humile increases feeding time with increasing sucrose concentration, 18 as do other ant species.…”

“…18,23,24 However, ants spent less time feeding from hydrogels with increasing sucrose concentration. This was unexpected because when feeding from liquid droplets, L. humile increases feeding time with increasing sucrose concentration, 18 as do other ant species. [23][24][25] The intake rate (volume ingested in a given time) remained constant until the sucrose concentration was 40%, after which the intake rate reduced.…”

“…We measured the length and height of the gaster directly from the videos; the width of the gaster (not visible from side view) was estimated from the relationship width:length = 1.0:1.1 determined for L. humile. 18,19…”

Effect of Starvation on the Feeding Activity Toward Sugary Food in the Ant Tapinoma nigerrimum (Nylander, 1856)

“…Finally, although carbohydrates are central resources for the ants, since the need for sugary sources may affect their behavior, from the interspecific interaction to the collective decision-making (e.g. Grover et al, 2007;Arganda et al, 2014;Sola & Josens, 2016;Frizzi et al, 2018;Wittman et al, 2018), an interesting improvement of the study would be to repeat the experiment with foods rich in fats or proteins, maybe including some different indicators in the analysis, such as hormone secretion, frequencies of trophallaxis and recruitment behavior. Moreover, we selected these experimental solutions on the basis of previous studies, which showed a clear scalar response of workers.…”

Parallel foraging cycles for different resources in leaf‐cutting ants: a clue to the mechanisms of rhythmic activity

“…Trophallactic feeding with fruit juices could provide a separate stimulus for fruit harvesting. Sugar concentration of solutions distributed through trophallaxis affects recruitment of foragers in Linepithema humile (Sola & Josens, ), and fruit odours could be used by recruits to target berries rather than leaves (cf. odour‐based targeting in Camponotus mus ; Provecho & Josens, ).…”