Comparative feeding behaviour of native and introduced terrestrial snails tracks their ecological impacts

By

Hoxha, Tedi
Crookes, Steve
MacIsaac, Ian
Chang, Xuexiu
Johansson, Mattias
Dick, Jaimie T. A.
Nicolai, Annegret
MacIsaac, Hugh

Type

Article

Date of Publication

2019

Original Publication

NeoBiota : advancing research on alien species and biological invasions

Volume

47

Pages

81-94

Subjects

Alien species , functional response , interspecific competition , non-indigenous species

Contributed by

Pensoft Publishers

Language

English

Published by

Sophia, Bulgaria Pensoft Publishers

Identifiers

DOI: https://doi.org/10.3897/neobiota.47.35000

 

Abstract

A developing body of theory and empirical evidence suggest that feeding behaviour as measured by the functional response (FR) can assist researchers in assessing the relative potential, ecological impacts and competitive abilities of native and introduced species. Here, we explored the FRs of two land snails that occur in south-western Ontario, one native (Mesodonthyroidus) and one non-indigenous (Cepaeanemoralis) to Canada. The non-indigenous species appears to have low ecological impact and inferior competitive abilities. Consistent with theory, while both species conformed to Type II functional responses, the native species had a significantly higher attack rate (5.30 vs 0.41, respectively) and slightly lower handling time (0.020 vs 0.023), and hence a higher maximum feeding rate (50.0 vs 43.5). The non-indigenous species exhibited a significantly longer time to contact for a variety of food types, and appeared less discriminating of paper that was offered as a non-food type. The non-indigenous species also ate significantly less food when in mixed species trials with the native snail. These feeding patterns match the known low ecological impact of the introduced snail and are consistent with the view that it is an inferior competitor relative to the native species. However, field experimentation is required to clarify whether the largely microallopatric distributions of the two species in south-western Ontario reflect competitive dominance by the native species or other factors such as habitat preference, feeding preferences or predator avoidance. The relative patterns of feeding behaviour and ecological impact are, however, fully in line with recent functional response theory and application.