Behavioral response to heat stress of twig-nesting canopy ants

Abstract

Tropical forests experience a relatively stable climate, but are not thermally uniform. The tropical forest canopy is hotter and thermally more variable than the understory. Heat stress in the canopy is expected to increase with global warming, potentially threatening its inhabitants. Here, we assess the impact of heating on the most abundant tropical canopy arthropods—ants. While foragers can escape hot branches, brood and workers inside twig nests might be unable to avoid heat stress. We examined nest choice and absconding behavior—nest evacuation in response to heat stress—of four common twig-nesting ant genera. We found that genera nesting almost exclusively in the canopy occupy smaller cavities compared to Camponotus and Crematogaster that nest across all forest strata. Crematogaster ants absconded at the lowest temperatures in heating experiments with both natural and artificial nests. Cephalotes workers were overall less likely to abscond from their nests. This is the first test of behavioral thermoregulation in tropical forest canopy ants, and it highlights different strategies and sensitivities to heat stress. Behavioral avoidance is the first line of defense against heat stress and will be crucial for small ectotherms facing increasing regional and local temperatures.

Ant communities and their trophobionts shape the incidence of pests and diseases in Indonesia’s coffee agroforestry system

“…Meanwhile, T. albipes can be found behind the moss and lichen that grows on stems and twigs. Ants of the genus Camponotus and Crematogaster also have diverse nesting habits from ground to canopy (Fernandes et al 2014;Ronque et al 2018;Bujan and Yanoviak 2022). Camponotus sp.3 nests were found in the curling leaves, whereas several large Crematogaster sp.1 nests were found on the main stem of the coffee plant.…”

Mutualisms in a warming world

“…Trait performance across a thermal gradient can respond to the frequency, intensity, duration and/or rate of warming (Sinclair et al, 2016). Changes in performance can be caused by both heritable and non‐heritable factors, including behaviour, plasticity, acclimation and/or evolution (Abram et al, 2017; Bujan & Yanoviak, 2022; Diamond, Chick, Perez, Strickler & Martin 2017; Salachan et al, 2021; Salsbery & DeLong, 2021; Sinclair et al, 2016; Sohlström et al, 2021; Tüzün & Stoks, 2018; Woods et al, 2021). When considering the thermal ecology of interacting species, however, it is necessary to take multiple TPCs into account (Berg et al, 2010; Cohen et al, 2017; Dell et al, 2014; Mauro et al, 2022; Tüzün & Stoks, 2018).…”