A chimpanzee’s time to feast: seasonality of Macrotermes flight hole activity and alate dispersal flights detected by termite-fishing experiments and camera traps in the Issa Valley, Tanzania

Abstract

IntroductionInvestigation into chimpanzee termite-fishing behavior has provided invaluable insights into the evolution of animal tool use and culture. However, research to date often overlooks how the ecology of termites may shape the nature of this predator–prey interaction. Though anecdotal links between meteorological factors, termite dispersal flights and the ability of chimpanzees to termite-fish have been made, these relationships were never empirically tested. In this study, we examined if and how the reproductive ecology of mound building termites (Macrotermes subhyalinus) affects the availability of this resource to termite-fishing chimpanzees in the Issa Valley, Tanzania.MethodsWe utilized in-person termite-fishing experiments, remote camera trap footage, as well as meteorological data to model both the availability of termite prey across seasons for chimpanzees as well as the timing of dispersal flights of the termite reproductive caste (alates). Additionally, we describe the predator diversity that characterizes alate swarming events during their seasonal dispersal flights.ResultsWe identify strong relationships between meteorological factors, Macrotermes alate dispersal flights and vulnerability of the colony to predation. As rainfall accumulates, Macrotermes become more abundant in their flight holes and are thus more vulnerable to researcher termite-fishing experiments. This increased accessibility to Macrotermes continues until alate dispersal flights which we also find are linked to cumulative rainfall as well as negatively correlated to wind speed.DiscussionThis type of baseline data on Macrotermes ecology is fundamental when forming hypotheses and designing studies into topics such as chimpanzee culture, tool-use, and foraging cognition.

Ecological correlates of chimpanzee termite fishing behavior in Mbam & Djerem National Park, Cameroon

“…Our study focused on whether seasonal termite fishing by Nigeria‐Cameroon chimpanzees ( P. t. ellioti ) in central Cameroon was consistent with the “necessity” and/or “opportunity” hypotheses for tool‐use behavior. Our findings revealed a relationship between rainfall, termite accessibility, and termite consumption by chimpanzees that is consistent with the “opportunity hypothesis” and with recent findings from a chimpanzee community in east Africa (Phillips et al., 2023 ).…”

“…Previous work examining seasonal termite reproductive behavior for mound‐building termites suggests they cue mating flights based on environmental signals. Mating flights for Macrotermes species, a well‐known target of chimpanzee termite fishing, have been shown to be triggered by rainfall, which aligns with the findings of this study (Mitchell, 2008 ; Phillips et al., 2023 ). Other research has also identified temperature, wind speed, and humidity as important factors determining the timing of termite reproductive behavior (Mitchell, 2008 ).…”

“…This aligns with conditions in MDNP during the small rainy season, where temperatures are high and rainfall begins increasing, which could create humid conditions that precede termite mating flights. Thus, our findings suggest that as rainfall increases during this period, members of the termite colony appear to move closer to the surface of their mounds, increasing abundance in flight holes, where the defensive behavior of termite soldiers is exploited by chimpanzees during termite fishing (Nishida et al., 1999 ; Phillips et al., 2023 ).…”

“…( 2023 ) found that termite fishing seasonality in a chimpanzee community in Issa Valley, Tanzania, was shaped in part by termite accessibility relating to termite reproductive behavior. Researchers observed that rainfall, humidity, and wind speed in this region were associated with dispersal flights of reproductive Macrotermes alates and that this behavior was accompanied by increased termite abundance in mound flight holes that made them more vulnerable to researcher‐based termite fishing experiments (Phillips et al., 2023 ). In this study, we examined seasonal fluctuations in termite fishing, a well‐documented chimpanzee tool‐using behavior where a plant probe is inserted into termite mounds to extract termites (Boesch et al., 2020 ; Goodall, 1964 ), in a community of P. t. ellioti in Mbam & Djerem National Park (MDNP) in central Cameroon.…”

“…The findings of Phillips et al. ( 2023 ) suggest that chimpanzees may be taking advantage of increased termite activity around reproductive periods and that termites may be otherwise inaccessible to chimpanzees during other parts of the year. In this study, we tested this possibility in an unhabituated community of P. t. ellioti in MDNP where anecdotal evidence has revealed a highly seasonal period of termite fishing.…”