What drives patrolling behaviour by nasute termites? A model and an empirical assessment

Abstract

Animals have evolved a number of antipredator strategies, which can reflect both intrinsic and extrinsic factors related to predation risk. In many termite species, a chemically armed soldier caste known as “nasute” engages in patrols upon breaching of foraging galleries, suggesting an adaptive response to imminent risk of mortality. However, the drivers of this collective behaviour are poorly understood. Here, I describe and test a qualitative model of patrolling behaviour upon gallery breaching by the arboreal termite Nasutitermes corniger (Termitidae: Nasutitermitinae). Patrolling behaviour is postulated to change throughout colony ontogeny, thus scaling with colony size. Further, this pattern is expected to be modulated by extrinsic cues for predation risk. Accordingly, patroller number increased with tree circumference at breast height, a surrogate for colony size. However, for any tree size, more soldiers engaged in patrols after repeated breaching, suggesting sensitization to structural damage. In parallel, patrolling rate (i.e., patroller number per time unit) was higher in smaller trees due to a disproportionate increase in patrol duration with patroller number. However, this response only occurred after repeated breaching; otherwise, patrolling rate was constant across tree sizes. Overall, patrolling behaviour by N. corniger seems to reflect intrinsic risks related to colony growth, adjusted by the extrinsic risk imposed by structural damage.

Escaping and repairing behaviors of the termite Odontotermes formosanus (Blattodea: Termitidae) in response to disturbance

“…Here we did not differentiate soldier and worker O. formosanus because only a few foragers (<1%) are soldiers ( Soleymaninejadian et al, 2014 ). Also, no new behaviors (such as patrolling observed in N. corniger ( Pequeno, 2017 ) were observed in soldier O. formosanus compared to workers once the mud tube was damaged.…”

“…A few studies have focused on the behavioral responses of termites to damaged foraging galleries and mounds in the field. For example, Pequeno (2017) reported that after a breach (1-cm long) was opened in the foraging gallery, some soldiers (ranging from 1 to 12) of Nasutitermes corniger (Motschulsky) patrolled in the open area (lasting from 2 to 292 s). Zachariah et al (2017) reported that workers of Odontotermes obesus (Rambur) repaired the broken mound by attaching various materials (e.g., soil particles and grass fragments of different sizes) along the entire circumference of the breach.…”

Termite Foraging on Plants of a Brazilian Savanna: the Effects of Tree Height

“…Larger plants are more attacked by termites than smaller plants possibly because: (i) they offer more food to termites (Gonçalves et al, 2005), (ii) they present better possibilities for foraging activities (Jones & Gathorne-Hardy, 1995;Gonçalves et al, 2005), and/or (iii) they provide better opportunities to escape predators (Neves et al, 2014;Pequeno, 2017). Furthermore, larger plants may constitute a better resource for tree-nesting termites.…”