Foraging Activity Rhythms of Dinoponera quadriceps (Hymenoptera: Formicidae) in Its Natural Environment

Abstract

This study characterizes the foraging activity of the queenless ant Dinoponera quadriceps (Kempf) (Hymenoptera: Formicidae) in its natural environment by testing the hypotheses that foraging activity presents both daily and seasonal rhythmic variations, and that these rhythms are related to environmental variables. Four colonies of D. quadriceps were observed in an area of secondary Atlantic forest in northeastern Brazil. Data collection was performed over 72 h every three months during an annual cycle. Both daily and seasonal foraging activity rhythms of D. quadriceps colonies were related to environmental factors, but colony differences also explained part of foraging variations. Foraging activity of D. quadriceps colonies was predominantly diurnal independently of season. In the early dry season, the colonies had two activity peaks, one in the morning and another in the afternoon, with a decrease in foraging at midday; however, during the rest of the year, foraging activity was distributed more evenly throughout the daylight hours. The daily rhythm of foraging activity was likely determined by an endogenous circadian rhythm year-round, but in the dry season, temperature and relative humidity also influenced daily foraging activity, with a negative effect of temperature and a positive effect of relative humidity. On a seasonal scale, foraging activity peaked in the early dry season and suddenly declined at the end of this season, increasing again at the late rainy season. The seasonal rhythm of foraging was negatively related to relative humidity and positively related to prey availability.

Ants as indicators of environmental change and ecosystem processes

“…Season was an abiotic factor that also influenced the incidence and species richness of ants, with higher ant incidence during the drier season. This typical finding (Basu, 1997;El Keroumi et al, 2012; but also see Castro et al, 2012) might be attributed to higher foraging activity at higher temperatures (Medeiros et al, 2014), seasonal changes in the brood cycle, or availability of nest sites or food (Levings, 1983). However, in our study, higher ant activity did not seem to translate into higher predation in the herbal and shrub layers, but might be instead limited to ground-foraging activity (see subsection 4.3).…”

“…Surprisingly, the predation of artificial caterpillars was significantly higher in the wetter season than in the drier season, which contrasts the pattern of higher ant incidence (respectively richness) during the drier season. This finding could be explained by the positive relationship between resource availability and foraging activity of ants (Medeiros et al, 2014; but also see Raimundo et al, 2009). For instance, a peak of predation rates on artificial caterpillars during the wetter season has also been found in sub-montane forests in Uganda (Molleman et al, 2016).…”

Individual Ants Do Not Show Active-rest Rhythms in Natural Nest Conditions

“…However, the result that foragers lose their circadian rhythms under colony conditions is inconsistent among studies. In social insects, such as bees and ants, foragers have precise daily rhythms (Bloch et al, 2001; Bochynek et al, 2017; Hoenle et al, 2019; Jürgen Stelzer et al, 2010a; Lei et al, 2019; Medeiros et al, 2014; Mildner and Roces, 2017; Moore et al, 1998; Orivel and Dejean, 2002; Passera et al, 1994; Raimundo et al, 2009; Retana et al, 1992). There are two possible reasons for this contradiction.…”

Litter Surface Temperature: A Driving Factor Affecting Foraging Activity in Dinoponera lucida (Hymenoptera: Formicidae)

“…Dinoponera lucida commonly prey upon epigeic ectotherm taxa, and these prey respond to temperature, which alters its density and availability (May, 1979;Colinet et al, 2015;Pincebourde & Suppo, 2016;Welch et al, 2020). We expect that D. lucida will adapt foraging time to maintain an optimal strategy (Norberg, 1977;Bernstein, 1979;Azevedo et al, 2014;Medeiros et al, 2014).…”