Temporal and geographic variation in parasitoid attack with no evidence for ant protection of the Melissa blue butterfly, Lycaeides melissa

Abstract

1. Interactions among caterpillars, ants and parasitoids have informed much of what is known about tritrophic ecological dynamics. However, detailed studies encompassing all three trophic levels are limited to relatively few natural systems. In this study, interactions of the Melissa blue butterfly, Lycaeides melissa, with mutualistic ants and parasitoids in the context of novel host plant use by the butterfly were investigated.2. Over the course of 2 years, 526 caterpillars and 288 ants tending caterpillars were collected from 185 plants at sites with two different native host plants and the exotic host alfalfa, for the purpose of investigating if the presence of ants was associated with reduced rates of parasitism.3. The abundance and diversity of parasitoids varied considerably across space and time. The presence of tending ants did not appear to reduce rates of parasitism, in contrast to a previous study of L. melissa, which found evidence of ant protection against spiders and other predators.4. This study has increased our understanding of ant-caterpillar-enemy interactions, and previously unobserved interactions have been documented, including at least two new host-parasitoid relationships. These findings highlight the importance of investigating ecological interactions, including interactions with other trophic levels, when studying diet breadth and ecological diversification in herbivorous insects.

Additive and interactive effects of anthropogenic stressors on an insect herbivore

“…As caterpillars, L. melissa develop over four instars over the course of approximately one month. In the wild, L. melissa caterpillars frequently engage in a facultative mutualism with ants, in which sugary secretions are exchanged for protection that is effective against generalist predators but apparently not from parasitoids [44,50]. Gravid females were collected from two sites in Verdi, Nevada, on the east side of the Sierra Nevada Mountains and the western edge of the Great Basin Desert, and were placed into outdoor oviposition chambers with A. canadensis to obtain eggs following methods used previously [48].…”

“…As caterpillars, L. melissa develop over four instars over the course of approximately one month. In the wild, L. melissa caterpillars frequently engage in a facultative mutualism with ants, in which sugary secretions are exchanged for protection that is effective against generalist predators but apparently not from parasitoids [44,50].…”

Exploring spatial and temporal patterns of viral infection across populations of the Melissa blue butterfly

“…At 14 of the sites sampled in 2020, tissue samples from L. melissa host plants were obtained. Because ants are known to tend L. melissa larvae at many of these locations, ants (Formicidae: mostly of the genus Formica ) and ant‐tended treehoppers (Membracidae: Campylenchia ) found on each plant were also collected (Scholl et al, 2014). Plants were selected systematically to represent the entire locality, with an emphasis on maximising the density of arthropods collected.…”

Combining Experimental Evolution and Genomics to Understand How Seed Beetles Adapt to a Marginal Host Plant

“…Future experiments and genomic analyses in this system will build on the results presented here, with the eventual aim of producing a predictive genotype-phenotype-fitness map for C. maculatus adapting to lentil. Comparisons with other systems, especially those where host adaptation does not involve high mortality and a severe bottleneck or where host shifts also include interactions with competitors, mutualists, or predators (e.g., [123][124][125]), could help determine what aspects of the genotype-phenotype-fitness map are general versus specific to this system.…”