Dataset: Intraspecific competition in antlion larvae

Increasing population density may be particularly important for the selection of hunting sites by sit-and-wait predators, such as pit-building antlions. The objective of our study was to experimentally investigate the effects of intraspecific competition on substrate choice, displacement, and trap size in the antlion <i>Myrmeleon timidus</i>. Third instar antlion larvae were placed in plastic containers (45 × 30 cm, 10 cm deep) with two substrates (5 cm in depth) differing in particle size (fine and coarse). Ten containers received 5 individuals each (high competition treatment; T5), while another 10 received 2 individuals each (low competition treatment; T2). Antlion larvae were carefully placed in the center line of the containers, at the point where the two types of substrates meet. The frequency of traps in the coarse substrate was low (8% in T5 and 15% in T2) and did not differ significantly between competition treatments. Larval displacement (i.e., distance from each trap to the center line) was significantly greater in T5 compared with T2. Neither trap diameter nor depth differed significantly between treatments, but the frequency of small traps was significantly greater in T5 compared with T2. Our findings indicate that <i>M. timidus</i> exhibits a marked preference for fine-grained substrates for pit construction, regardless of competition intensity. Conversely, our results suggest that an increase in biotic interactions (i.e., exploitation and interference competition) at higher population densities likely compels antlions to displace farther to establish their traps and to construct smaller traps more frequently.