Comparative analysis of experimental testing procedures for the elicitation of rescue actions in ants

Abstract

Rescue behaviour is observed when one individual provides help to another individual in danger. Most reports of rescue behaviour concern ants (Formicidae), in which workers rescue each other from various types of entrapment. Many of these entrapment situations can be simulated in the laboratory using an entrapment bioassay, in which ants confront a single endangered nest mate entrapped on a sandy arena by means of an artificial snare. Here, we compared numerous characteristics of rescue actions (contact between individuals, digging around the entrapped individual, pulling at its body parts, transport of the sand covering it and biting the snare entrapping it) in Formica cinerea ants. We performed entrapment tests in the field and in the laboratory, with the latter under varying conditions in terms of the number of ants potentially engaged in rescue actions and the arena substrate (marked or unmarked by ants’ pheromones). Rescue actions were more probable and pronounced in the field than in the laboratory, regardless of the type of test. Moreover, different test types in the laboratory yielded inconsistent results and showed noteworthy variability depending on the tested characteristic of rescue. Our results illustrate the specifics of ant rescue actions elicited in the natural setting, which is especially important considering the scarcity of field data. Furthermore, our results underline the challenges related to the comparison of results from different types of entrapment tests reported in the available literature. Additionally, our study shows how animal behaviour differs in differing experimental setups used to answer the same questions.

Injury shortens life expectancy in ants and affects some risk-related decisions of workers

“…At the same time, aggression toward heterospecifics was similar in both injured and intact workers. This supports a growing number of studies that indicate that ants are highly sensitive to the behavioral context (Duhoo et al 2017 ; Turza and Miler 2022 ). In the case of our study, we demonstrate diverging responses of ants to decreased life expectancy in the context of rescue and aggression.…”

Early social context does not influence behavioral variation at adulthood in ants

“…Determining which measures are relevant to reveal changes in behavioral variability in response to differences in the early environment is important but challenging. The identification of the sources of variability often requires the use of controlled and standardized conditions that are potentially disconnected from natural conditions (e.g., Watanabe et al 2012 ; Turza and Miler 2021 ). However, working in more natural environments is difficult because it may not be possible to determine whether the level of variability observed in adulthood is the result of specific developmental conditions or the context experienced at the time of observation.…”

Do They Know What They Are Doing? Cognitive Aspects of Rescue Behaviour Directed by Workers of the Red Wood Ant Formica polyctena to Nestmate Victims Entrapped in Artificial Snares

“…About twenty years ago, Czechowski et al (2002) [28] employed the term "rescue behaviour" in the title and the text of the paper describing rescue behaviour displayed by workers of three ant species (Formica sanguinea, Formica fusca and Formica cinerea) in response to ant victims captured by predatory antlion larvae (Myrmeleon formicarius). This study provided inspiration for further extensive research carried out both in the field and in the laboratory with the use of two main bioassays: antlion larva capture bioassay, during which ant rescue behaviour was elicited in response to an ant captured by an antlion larva [59][60][61][62][63] and artificial snare bioassay, during which ant rescue behaviour was elicited in response to a victim ant entrapped in an artificial snare [29,59,61,62,[64][65][66][67][68][69][70][71][72][73][74][75][76][77].…”