Temporal Dynamics of Scout Release-Behavior of Termitophagous Ponerine ant, Megaponera Analis

J Insect Behav (2024) 37:233–242 https://doi.org/10.1007/s10905-024-09864-9 RESEARCH Temporal Dynamics of Scout Release‑Behavior of Termitophagous Ponerine ant, Megaponera Analis Rifilwe V. Modiba · Christian W. W. Pirk Abdullahi A. Yusuf · Received: 31 January 2024 / Revised: 26 September 2024 / Accepted: 8 October 2024 / Published online: 5 November 2024 © The Author(s) 2024 Abstract Megaponera analis is an obligate termitophagous species endemic to sub-Saharan Africa. The species forages by sending out scouts to search for termites. Once termites are located, the scouts return to the nest and recruit nest mates. Scouts face unpredictable environmental conditions, including sudden flooding, temperature changes, high winds and predation by natural enemies. We observed 519 scouting trips from 18 different colonies over three years to determine how long it takes for the colony to replace a scout that has likely died while on scouting duty or is lost due to environmental perturbations. Study areas were at Maremani, Musina, Masebe and D’nyala Nature Reserves in the Limpopo Province of South Africa. We introduced definitions of scouting turnover, scouting trip, and scouting session. Scouting turnover is the time it takes a successive scout to leave the nest for a trip, whereas a scouting trip is the journey a scout takes from the nest in search of Supplementary Information The online version contains supplementary material available at https://doi. org/10.1007/s10905-024-09864-9. R. V. Modiba (*) · C. W. W. Pirk · A. A. Yusuf Social Insects Research Group, Department of Zoology and Entomology, University of Pretoria, Pretoria 0028, South Africa e-mail: ; R. V. Modiba Department of Biological and Agricultural Sciences, Sol Plaatje University, Kimberley 8300, South Africa food. Since M. analis shows bimodal foraging behavior, the morning observations were recorded as the first scouting session, while the subsequent session, which starts in the afternoon, was recorded as the second scouting session. The mean scouting turnover for all 519 trips was 9.36 ± 0.64 (SD) minutes. When turnover was divided into sessions, the first scouting session lasted a mean of 7.77 ± 12.17 (SD) minutes, while the second had 10.34 ± 18.32 (SD) minutes. The minimum turnover was zero minutes, and the maximum was 124 minutes. Keywords Scouting dynamics · termite predation · foraging behavior · nestmate recruitment · bimodal foraging Introduction In optimal foraging, communication is central to foraging success (Pyke and Starr 2021), and nest selection is equally critical for social insects as this affects the colony’s fitness (Healey and Pratt 2008; Evison et al. 2012). Generally, organisms approach foraging in individual scouting or group searching (DechaumeMoncharmont et al. 2005). Foraging strategies utilized by different species of ants depend on the environment and habitat where they are found (Gibb and Parr 2013), and these conditions have driven the foraging in some species to be bimodal. Vol.: (0123456789) 234 Benefits of group searching include sharing information such as food source availability (DechaumeMoncharmont et al. 2005); however, encountering a predator or sudden change in environmental conditions can be detrimental to the colony, and this is where individual scouting has an advantage. Scouts play a pivotal role in locating and quantifying food resources and making critical decisions that affect the entire colony, such as hunting for new nest locations (Franks et al. 2002). Both communication and nest selection are mostly the scouts’ responsibility, making scouts’ decisions central to the colony’s survival. Biesmeijer and De Vries (2001) have differentiated between a scout and a recruit by defining a scout as an individual tasked with searching for food independently, whereas the recruit depends on the scout and nest mates for information on food sources. The scouting rate of ants is significantly influenced by nest size, with polydomous nests experiencing lower scouting rates than monodomous nests (Cao 2013). Scouts face unpredictable natural phenomena like floods and gusty winds, and how the colonies respond to these threats is unknown. Eusocial insects are characterized by a high degree of division of labor with specific tasks such as foraging, caring for the young, and nest construction and maintenance allocated to individuals (Gordon 2002). Ants are particularly sensitive to microclimatic changes, which can influence nesting behavior (Karlik et al. 2016) and foraging (Hölldobler and Wilson 1990), and scouts should communicate these changes to nest mates for collective decision-making. Scouting in Megaponera analis (syn. Megaponera foetens and Pachycondyla analis) occurs bimodally, with some scouting happening from the early morning to about 11:00 am local time, while the next session starts in the late afternoon and early evenings (Longhurst et al. 1979; Longhurst and Howse 1979; Yusuf et al. 2013; Frank and Linsenmair 2017a, b; Frank et al. 2018a, b) and at night (Yusuf et al. 2013). Bimodal foraging is also practiced in non-ponerine ants, and the driving factor is likely temperature, with the foraging peaking at both sides of temperature extremes (Cerdá et al. 2009). It is currently unknown why scouting is not continuous, but this trait appears phylogenetically conserved as it is shared with Ophthalmopone berthoudi, which is sister genus to M. analis (Schmidt 2013) and also has bimodal foraging activity (Crewe and Peeters 1987). Literature, however, suggests that bimodality Vol:. (1234567890) J Insect Behav (2024) 37:233–242 could be influenced by the unavailability of the termites during hotter midday hours since termites are prone to desiccation (Hewitt et al. 1972; Longhurst et al. 1979). Scouting distance can reach 95 m, and searching can last over an hour (Longhurst and Howse 1979; Yusuf et al. 2014). Scouts use termite soil sheets as kairomones to aid them in finding food sources quickly (Longhurst and Howse 1978; Yusuf et al. 2014). When the scout locates a food source, it quantifies it and returns to the nest to recruit nestmates, laying a trail pheromone (Longhurst et al. 1978). The trail lasts up to 29 h (Hölldobler et al. 1994), thereby improving raid position fidelity until termite prey are exhausted (Bayliss and Fielding 2002), and the scout always uses the fastest way possible to the nest (Frank et al. 2018a). When the scout arrives at the nest, it recruits between 200 and 800 nestmates back to the site, where it finds termites (Frank et al. 2017; Yusuf et al. 2020). The scout will lead a group of nest mates who walk in a column formation. The scout will be ahead of the column, and behind it will be former scouts, while at the back end of the column will be major ants, and these workers maintain position fidelity (Frank and Linsenmair 2017b). Although raids in M. analis have been studied in detail, little is known about the dynamics of scouting and (...truncated)