Different response of a native dragonfly species against a neonative invader along a latitudinal gradient

Abstract

The poleward expansion of various organisms is accelerating due to global warming, but many aspects of these biological invasions remain unclear. One less documented aspect is the competition among native and invader species (so-called neonatives) with similar ecological niches along a latitudinal gradient. In this study, we compared the foraging behaviors across latitudes between nymphs of the native dragonfly Orthetrum albistylum speciosum from four different Japanese regions when confronted with its neonative counterpart, Trithemis aurora. The foraging intake of O. albistylum speciosum nymphs from low-latitude regions did not change in the presence of T. aurora, whereas native populations from higher latitudes had significantly lower intakes. Our findings imply that while no clear impacts by the neonative species are found at present, threats are expected to be more severe if the invader expands its distribution to northern regions as global warming continues unabated.

Keywords: ecology; entomology.

Graphical abstract

Figure 1

Distribution of T. aurora, a poleward-expanding invader dragonfly considered nowadays a neonative species in Japan This dragonfly originated in Southeast Asian regions and Taiwan, under subtropical and tropical climates, and was first detected in subtropical Ishigaki-jima Island (southwest Japan) in 1981,^, then in Okinawa Island in 1983, Amami-Oshima Island in 1988, the southern Kyushu district (Kagoshima Prefecture) in 1999, and the Shikoku district by the late 2000s^, The distribution of T. aurora extended to the central Kinki district (Nara Prefecture) in 2020. When the global warming scenario made by the IPCC becomes a reality, its distribution could extend to northern Japan—Miyagi Prefecture under SSP1-2.6 scenario, or Hokkaido under SSP5-8.5 scenario—by the end of this century. Symbols in this figure indicate: , native range of T. aurora; , its already invaded regions; , latest region of T. aurora detection; , regions where this species is predicted to reach by the end of 21th century due to global warming. Photo of T. aurora by Shunsuke Yamamoto.

Figure 2

Effects of temperature and the presence of a competitor on the foraging intakes of native and neonative dragonfly nymphs (A–H) Influence of the bioinvasion scenarios of the neonative species (pre- or post-invasions) on the foraging intakes (the number of prey consumed) of nymphs of four O. albistylum speciosum (native) regional populations (A, Hokkaido; C, Miyagi; E, Nara; G, Kochi) at three different temperature conditions. Influence of four O. albistylum speciosum (native) regional populations (B, Hokkaido; D, Miyagi; F, Nara; H, Kochi) on the foraging intakes (the number of prey consumed) of nymphs of T. aurora (neonative) under the same temperature conditions. Fitted curves and bands for 95% confidence interval with GLMMs. The icons indicate the significant effects (p < 0.05); NS shows non-significant effects. The results for Nara are modified from Figure 2 of Nagano et al. See also Tables 1 and 2.