Effects of group size and starvation on survival of the Asian subterranean termite Coptotermes gestroi (Isoptera: Rhinotermitidae)

Abstract

Coptotermes gestroi forages on wooden structures and causes substantial damage in urban areas of Brazil. The survival of foragers may be influenced by either group size or caste composition. It was hypothesised that workers survive at higher rates in larger groups and consequently exhibit higher rates of food consumption and that soldiers represent a nutritional resource for foragers during starvation periods. To test the first hypothesis, groups of 100, 200 and 400 workers were placed in experimental arenas containing wood as food. After 28 days, the units were evaluated and the number of living termites and wood consumption were estimated and compared. An analysis of the data found that there were no significant differences within the group sizes on termite survival but that relative wood consumption was significantly higher in the smaller groups. To test the second hypothesis, groups containing workers and soldiers (9:1 ratio) or only workers were placed in experimental arenas with food present or absent. Survival for each caste was monitored at 3 day intervals over 9 days to estimate the cannibalism rate. Cannibalism was significantly higher in the starved groups, but the presence of soldiers did not influence the rate of cannibalism. Colony fragmentation and starvation are stressful conditions that lead foragers of C. gestroi to adaptive behaviours in order to enhance their survival.

Behaviours indicating cannibalistic necrophagy in ants are modulated by the perception of pathogen infection level

“…In hunger condition, a lot of workers die from starvation, so eating their corpses can counterbalance the negative consequences of the stress induced by food deprivation. This result corresponds with other findings in which a food shortage led to a growing rate of conspecific cannibalism in wood ants 15 , 16 , as well as of both alive individuals and corpses in termites 47 , 48 or kin larvae in social bees 12 . On the other hand, conspecific necrophagy in F. polyctena also underpins the presence of collective corpse consumption, which enhances the possibility of the spread of diseases 27 , 28 .…”

Termite Resistance of Impregnated Jabon Wood (Anthocephalus Cadamba Miq.) with Combined Impregnant Agents

“…Thus, cellulose could not be digested, termites would be starving, stress and cannibalism would be likely to occur (Nandika, 2015;Hu et al, 2011;Poinar, 2009). Cannibalism is an adaptive behaviour to survive in the colony (Haifig et al, 2017).…”

It is not only group size: Soldiers also modulate the tolerance to insecticide in termites (Blattodea: Isoptera)

“…In termites, studies on social facilitation are mainly associated with the effect of the group on the survival of individuals in stressful situations, such as food deprivation (Miramontes & DeSouza 1996; Haifig et al . 2018), pathogen infection (Rosengaus et al . 1998) and insecticide poisoning (DeSouza et al .…”

“…In termites, studies on social facilitation are mainly associated with the effect of the group on the survival of individuals in stressful situations, such as food deprivation (Miramontes & DeSouza 1996;Haifig et al 2018), pathogen infection (Rosengaus et al 1998) and insecticide poisoning (DeSouza et al 2001;Santos et al 2004). These studies have shown in common the longest survival time as the number of individuals per group (or density) increases.…”