Diurnal and nocturnal foraging specialisation in Neotropical army ants

Abstract

Temporal segregation of species' activity periods may lessen interspecific competition. e tested for temporal segregation among Neotropical army ants (Formicidae: Dorylinae). Co‐occurring species overlap on prey resources, and regular colony movements and long‐distance raiding increase interspecific interference. We hypothesised interspecific competition selects for temporal separation of species' raid periods into diurnal versus nocturnal activity. We predicted species would differ significantly in their timing of foraging. We further predicted timing would differ among congeners because close relatives likely overlap in resource needs. Trail walk encounter rates were used to estimate species' diurnal versus nocturnal foraging activity at four Neotropical sites. Army ant species differed significantly in foraging times. There were significantly diurnal and nocturnal specialists; some species foraged at similar rates day and night. Two genera (Eciton and Neivamyrmex) included both diurnal and nocturnal specialists. Relative eye size (a morphological indicator of above‐ground activity) was positively associated with diel foraging specialisation (both diurnal and nocturnal). Temporal separation of foraging times may play a role in allowing Neotropical army ant species to occupy the same habitat. Diel specialisation may be a common mechanism for species coexistence in tropical forests where season‐based phenological changes are often moderated.

Hunting habits die hard: Conserved prey preferences in army ants across two distant neotropical rainforests

“…lucanoides . This finding, akin to the nuanced differences in prey preferences, accentuates a certain level of behavioral flexibility, as similarly demonstrated in prior studies comparing army ant activity across different regions (O'Donnell et al, 2009, 2020). Nevertheless, spatial and temporal predation preferences remained remarkably consistent overall across various geographic regions, thereby reinforcing the notion of relatively stable army ant raiding behaviors.…”

“…prior studies comparing army ant activity across different regions (O'Donnell et al, 2009(O'Donnell et al, , 2020. Nevertheless, spatial and temporal predation preferences remained remarkably consistent overall across various geographic regions, thereby reinforcing the notion of relatively stable army ant raiding behaviors.…”

“…Lastly, Ecuadorian army ants exhibited niche differentiation not just in their dietary preferences, but also in their spatiotemporal raiding patterns, likely to reduce interspecific competition (Hashimoto & Yamane, 2014;Hoenle et al, 2019;O'Donnell et al, 2009O'Donnell et al, , 2020Powell & Baker, 2008;Rettenmeyer et al, 1983). For example, Ec.…”

“…In Costa Rica and Venezuela, the raids of Ec. vagans were primarily confined to the nighttime (Hoenle et al, 2019; O'Donnell et al, 2020). Contrarily, our observations in Ecuador did not reveal any such diel specialization.…”

Divergent Circadian Foraging Strategies in Response to Diurnal Predation Versus Persistent Rain in Asian Weaver Ant, Oecophylla smaragdina, Suggest Possible Energetic Trade-offs

“…As a result of parasitic fly interventions, the feeding cycle of Atta cephalotes is delayed throughout the day and induces nocturnal activities (Orr, 1992). The diel specialization phenomenon enables species to coexist in the same habitat, particularly in cases where season-based phenological changes or temporal separation of foraging times are moderated (O’Donnell et al, 2021).…”