Can Estivation Preferences Be Used to Develop Novel Management Tools against Invasive Mediterranean Snails?

Priscillia Hanache,Gaylord A Desurmont,Thierry Thomann,Valerie Caron

doi:10.3390/insects12121118

Priscillia Hanache, Gaylord A Desurmont + Show 2 more

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https://doi.org/10.3390/insects12121118

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Journal: Insects	Publication Date: Dec 14, 2021
Citations: 1	License type: CC BY 4.0

Affiliation: Jean Monnet University, CSIRO Health and Biosecurity

Abstract

Simple SummaryTerrestrial snails living in warm and dry climates had to develop strategies to survive. Several species climb on vertical supports when temperatures rise and spend the warmest months resting, typically in groups. Understanding this behavior could be useful in developing new management tools for species that are invasive. Here, we focused on four invasive snail species, and assessed their preferences for vertical supports varying in widths and heights under laboratory and field conditions. We also tested whether the presence of other snails from the same or different species affected these preferences. The snails strongly preferred wider supports in laboratory choice tests, and one species (Theba pisana) preferred taller supports as well. Results were similar in the field, where more snails were found on wider and taller supports 24 h after being released. The percentage of snails found in groups on a support was strongly density-dependent. The presence of other snails or their mucus did not affect the choices made. Overall, our results point towards the possibility of developing attractive supports to trap snails in the field.Terrestrial snails that live in hot and dry climates have developed strategies to cope with high summer temperatures. Several species estivate during the warmest months of the years by resting on vertical supports, typically in groups. Understanding how snails choose their estivation sites and aggregate may lead to the development of new management tools in areas where these snails are invasive. Here, we investigated the preferences of four snail species for vertical supports varying in widths and heights under laboratory and field conditions, and tested whether the presence of conspecifics or snails of other species affected these preferences. The results show that the snails strongly preferred wider supports in laboratory dual-choice tests, and one species (Theba pisana) showed a consistent preference for taller supports as well. These results were confirmed in the field, where more snails were found on wider and taller supports 24 h after being placed in test quadrats. The percentage of snails found in groups on a support was strongly density-dependent. The presence of conspecifics or their mucus did not affect the choices of the snails, nor did the presence of snails of other species or their mucus. Taken together, these results could lead to the development of attractive supports that could be used to mass-capture snails in the field.

Highlights

Mollusks have evolved in aquatic environments, but some lineages have successfully colonized terrestrial environments [1,2]
Theba pisana always preferred the wider support, no matter the widths tested, while C. barbara and C. acuta preferred supports of 6.4 cm compared to 1.6 cm, and 1.6 cm compared to 0.4 cm, but did not discriminate between a 0.4-cm support and nothing
Estivation is a critical component of the ecology of terrestrial gastropods adapted to hot and dry climates

Summary

Introduction

Mollusks have evolved in aquatic environments, but some lineages have successfully colonized terrestrial environments [1,2]. Out of the 85,000 species of the Gastropoda (snails and slugs) species, an estimated 24,000 species are terrestrial. Land gastropods have evolved an array of morphological, physiological, ecological, and behavioral adaptations that enable them to reduce desiccation risks [3]. While some snails occupy consistently humid habitats, others have adapted to hot and dry environments, including deserts. One of the key strategies used by gastropods to cope with such harsh environments is estivation. Estivation is a diapause occurring during summer. In several Mediterranean snails, estivation occurs after snails have climbed onto vertical supports that are usually plants, but that can be manmade structures. Snails avoid hot ground temperatures [6,7]. The temperature decreases as the distance from the ground increases [8]. In Australia, clustering snails can be found on robust weeds in the field, which may provide increased moisture [10]

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