Ants in brown bear diet, and discovery of a new ant species for Estonia from brown bear scats
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Department of Zoology, Institute of Ecology and Earth Sciences, University of Tartu, Vanemuise 46, 51003 Tartu, Estonia
Marju Keis   

Department of Zoology, Institute of Ecology and Earth Sciences, University of Tartu
Online publication date: 2019-09-10
Publication date: 2019-09-10
Hystrix It. J. Mamm. 2019;30(2):112–119
For omnivorous brown bears, ants can seasonally constitute an important category of food with high nutritional value. A former dietary study conducted in Estonia revealed that the energy gained from animal and plant food was roughly equal, whereas the contribution of ants was almost 15%. Here, using the same dataset, we analyzed ant consumption by brown bears in Estonia at a greater taxonomic resolution and evaluated the preferences of brown bears towards different ant species by measuring the availability (biomass and mound density) of ants in the study area. Among the 18 species and five groups of ants in bear scats, members of the genera Lasius and Formica were the most abundantly consumed ant groups, considering both the volume and frequency of occurrence. Among the species we detected, Lasius niger and Formica polyctena dominated. However, these were not the favorite ant taxa for bears, that highly preferred Camponotus ants and avoided Myrmica ants. In addition, a new species (Camponotus fallax) for Estonian ant fauna was discovered, providing an example of how studies on mammal food habits can reveal elusive insect species that have remained undiscovered with traditional survey methods. The general pattern of the brown bear myrmecophagy in Europe is examined to place our results into a broader context.
We would like to dedicate this article to the memory of Dr. Ants-Johannes Martin, the best and foremost myrmecologist in Estonia, whose contribution to this work was crucial. He helped to identify large majority of the ant species for this study and assisted in planning the field works for the ant inventory. We are very grateful also to Ave Lind, a former student of A-J. Martin, for helping to identify the ant species. We thank two anonymous reviewers for their helpful comments and suggestions. This study was supported by the Environmental Investment Centre at the Estonian Ministry of Finance, The European Union through the European Regional Development Fund (Center of Excellence FIBIR), target financing grants SF0180122 and SF0170057, and institutional research funding grant IUT20-32 from the Estonian Ministry of Education and Science.