Co-occurrence of ecologically equivalent cryptic species of spider wasps.

Hiroaki Kurushima,Derek A Roff,Manabu Kato,Akira Shimizu,Katsuhiko Sayama,Kenta Watanabe,Yutaka Nishimoto,Eisuke Hasegawa,Jin Yoshimura,Jong-Kuk Kim,Jeong-Kyu Kim

doi:10.1098/rsos.160119

Abstract

Many cryptic species have been discovered in various taxonomic groups based on molecular phylogenetic analyses and mating experiments. Some sympatric cryptic species share equivalent resources, which contradicts the competitive exclusion principle. Two major theories have been proposed to explain the apparent lack of competitive exclusion, i.e. niche-based coexistence and neutral model, but a conclusive explanation is lacking. Here, we report the co-occurrence of cryptic spider wasp species appearing to be ecologically equivalent. Molecular phylogenetic analyses and mating experiments revealed that three phylogenetically closely related species are found sympatrically in Japan. These species share the same resources for larval food, and two of the species have the same niche for nesting sites, indicating a lack of competitive exclusion. This evidence may suggest that ecologically equivalent species can co-occur stably if their shared resources are sufficiently abundant that they cannot be over-exploited.

Highlights

Closely related species complexes with almost no morphological distinctions are designated as cryptic species
Molecular phylogenetic analyses based on the cytochrome oxidase subunit I DNA (COI) and 28S markers indicate that the WM, BM and EN types are separated into monophyletic groups
These analyses demonstrated five additional monophyletic groups: the Okinawa Island type (OI) type, Korean types 1 and 2 (K1 and Korean type 2 (K2)), European type 1 (E1 from France and England) and European type 2 (E2 from France)

Summary

Introduction

Closely related species complexes with almost no morphological distinctions are designated as cryptic species. Cryptic species have been reported to be distributed allopatrically, parapatrically [3] or even sympatrically [1]. These sympatric species occasionally exhibit minor differences in their ecological niches [4]. A few cryptic species exhibit no apparent differences in their ecological niches but still are distributed sympatrically over much of their distributions [5,6]. These findings appear to contradict the competitive exclusion principle [7,8,9,10]

Methods

Results

Conclusion