Toxicity and utilization of chemical weapons: does toxicity and venom utilization contribute to the formation of species communities?

Abstract

Toxicity and the utilization of venom are essential features in the ecology of many animal species and have been hypothesized to be important factors contributing to the assembly of communities through competitive interactions. Ants of the genus Monomorium utilize a variety of venom compositions, which have been reported to give them a competitive advantage. Here, we investigate two pairs of Monomorium species, which differ in the structural compositions of their venom and their co-occurrence patterns with the invasive Argentine ant. We looked at the effects of Monomorium venom toxicity, venom utilization, and aggressive physical interactions on Monomorium and Argentine ant survival rates during arena trials. The venom toxicity of the two species co-occurring with the invasive Argentine ants was found to be significantly higher than the toxicity of the two species which do not. There was no correlation between venom toxicity and Monomorium survival; however, three of the four Monomorium species displayed significant variability in their venom usage which was associated with the number of Argentine ant workers encountered during trials. Average Monomorium mortality varied significantly between species, and in Monomorium smithii and Monomorium antipodum, aggressive interactions with Argentine ants had a significant negative effect on their mortality. Our study demonstrates that different factors and strategies can contribute to the ability of a species to withstand the pressure of a dominant invader at high abundance, and venom chemistry appears to be only one of several strategies utilized.

Venom Function of a New Species of Megalomyrmex Forel, 1885 (Hymenoptera: Formicidae)

“…We confirmed with an authentic sample that the exclusive alkaloid of Megalomyrmex peetersi is trans-2-butyl-5-heptylpyrrolidine, which is also found in the venom of multiple species of Solenopsidini ants [15,25,28]. Research of Solenopsidini venom addresses several different topics, but we focused on possible antibiotic and insecticidal functions, given that M. peetersi is a soil-dwelling ant species likely to interact with microbial pathogens and other insect species through predation or competition.…”

“…Here we describe the new free-living species Megalomyrmex peetersi, which synthesizes trans-2-butyl-5-heptylpyrrolidine as its exclusive venom alkaloid. This alkaloid has previously been found in several Monomorium Mayr species [28,29], Solenopsis Westwood species [15,30], and other Megalomyrmex Forel species [24,25,31]. Given that M. peetersi sp.…”

“…According to the authors and with the specimen examined in this work, males of this species are morphologically recognized by (1) the presence of blackened piligerous punctures on the body surface ( Figure 3a Comments (Figure 3). Boudinot et al [28] described the male of this species as M. wallacei. According to the authors and with the specimen examined in this work, males of this species are morphologically recognized by (1) the presence of blackened piligerous punctures on the body surface ( Figure 3a…”

Beyond spider personality: The relationships between behavioral, physiological, and environmental factors

“…We speculate that aggressive spiders would experience a higher metabolic cost, as occurs in scorpions Parabuthus transvaalicus (Nisani et al., 2012), because this is associated with a higher concentration and quantity of venom required when subduing prey. It would be interesting, to test if aggressive spiders use different toxins during intraspecific competition, as occurs in the polyps of the aggregating sea anemone Anthopleura elegantissima (Macrander et al., 2015) and ants of the genus Monomorium (Westermann et al., 2015). Aggressive anemone polyps show a higher quantity of a particular type of gated potassium ion channel (toxins/Kunitz‐type protease inhibitor and type II acrorhagins; Macrander et al., 2015), whereas ants using venom to withstand attack from the invasive Argentine ant Linepithema humile show higher concentrations of toxins compared to populations of ants that do not live in close proximity to these invasive ants (Westermann et al., 2015).…”

Alteration of Bumblebee Venom Composition toward Higher Elevation

“…For instance, in predation, venom is expected to be positively selected when resources are limited because it confers a competitive advantage to predators [9]. On the other hand, in defense, venom is positively selected when predators are abundant because it confers a competitive advantage to preys [10,11]. These selective pressures have fostered changes in venom composition [4], resulting in adaptations to different environments, in turn leading to niche partitioning [12,13].…”