Gut content metabarcoding of three widespread Iberian ant‐eating spiders reveals specialisation on the same abundant harvester ants

• Published in: Ecological entomology Vol. 47; no. 3; pp. 305 - 313
• Main Authors: Ortiz, David, Petráková Dušátková, Lenka, Pekár, Stano
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-06-2022; Wiley Subscription Services, Inc
• Subjects: ant predators; Ants; arachnid diet; Biological control; Diet; Geographical distribution; Messor; Myrmecophagy; Prey; Species; Spiders; stenophagy
• ISSN: 0307-6946; 1365-2311
• DOI: 10.1111/een.13114

Trophic specialists often follow unique evolutionary pathways, show potential applications in biological control, and suffer from increased ecological vulnerability. The myrmecophagous spider genus Zodarion, highly diversified across the Mediterranean, is among the few predatory groups showing strict stenophagy. Most Zodarion species display narrow distributions, but a few of them occur across hundreds to thousands of kilometres, raising questions on the causes of their comparatively higher distributional success.
In this study, through extensive geographic sampling and the metabarcoding of gut contents, we explored the diets of the three most widely distributed Iberian species of Zodarion: Zodarion alacre and the two lineages of Zodarion styliferum.
Our data support the three species as strictly myrmecophagous, showing diets largely based on the granivorous Messor ants. Auxiliary prey includes other ants of the subfamilies Myrmicinae, Formicinae, and Dolichoderinae. The diet breadth of both Z. styliferum lineages was slightly narrower than that of Z. alacre, coinciding with their higher physiological and behavioural efficiency for predating on Messor.
We discard that the relatively large distribution range of our three focal Zodarion species is related to breaking the boundaries of myrmecophagy, and instead argue that such success could be favoured by their specialisation on Messor ants, which are also abundant and widespread across the Iberian Peninsula.
Zodarion alacre, Zodarion styliferum‐Western and Z. styliferum‐Eastern are confirmed as strictly myrmecophagous spiders.
The diets of these three spider species, which are widespread across the Iberian Peninsula, are largely based on Messor ants.
We suggest that the wide distribution and high abundance of their preferred prey is key for explaining the wide distribution of our three focal Zodarion species.