Niche overlap and host specificity in parasitic Maculinea butterflies (Lepidoptera: Lycaenidae) as a measure for potential extinction risks under climate change

Abstract

Species depending on specific biotic interactions are particularly threatened by environmental changes. Therefore, host dependency in species living in parasitic relationships is acknowledged as a crucial factor increasing climatic susceptibility and species decline. In Maculinea butterflies and Myrmica ants, a complex form of social parasitism brings the butterflies into dependency of some few associated ant species for reproductive success. We evaluated to what extent these relations can be attributed to similarity in their climatic niches and whether alterations in niche overlap might foster the climatic susceptibility in Maculinea butterflies under future climate change. We show that the niches of ants and butterflies differ significantly more than expected at random corresponding to the observed flexibility in host exploitation. Moreover, a generally low degree of niche overlap and similar niche overlap scores between main and secondary host associations argue for a low host specificity of Maculinea butterflies. Pronounced range shifts and habitat retractions in all species will result in severe spatial limitations of Maculinea species by the presence of their hosts. No tightening in any of the host-parasite associations was detected under the pressure of range restrictions. Niche overlap scores remain comparably low in future scenarios and call for the possibility of extensive host shifts between all related species. Therefore, the absence of niche constraints might enable the parasites to extensively shift among hosts to allow the co-occurrence of several Maculinea species, in principle using the same host, and to maintain viable populations under the pressure of limited distributions and changing environments.

The ecological niche of Echinococcus multilocularis in North America: understanding biotic and abiotic determinants of parasite distribution with new records in New Mexico and Maryland, United States

“…The second predicted distribution is more inclusive and represents the threshold that equates entropy of distributions at the threshold and original areas. This threshold has been proposed for organisms with high dispersal potential as they can reach distant areas in a relatively short time period (Filz andSchmitt 2015: Hill et al 2016). We interpret the resulting model as describing the subset of the realized niche represented in the study area (Peterson and Soberón 2012).…”

Rear‐edge populations are important for understanding climate change risk and adaptation potential of threatened species

“…To estimate and project the distribution of the Caucasian grouse, we used maximum entropy modeling (Maxent; Phillips, Dudík, & Schapire, 2004). Maxent, the most widely used SDM algorithm (Phillips et al, 2004), is a presence-only modeling technique (Elith et al, 2011), and has been consistently shown to outperform alternative approaches (Elith et al, 2006;Merow, Smith, & Silander, 2013;Srivastava, Griess, & Keena, 2020), especially when the number of presence records is small (Filz & Schmitt, 2015). To identify the best Maxent parameterization, we used the "kuenm" package in R (Cobos, Peterson, Barve, & Osorio-Olvera, 2019).…”

Niche determinants in a salamander complex: Does hybridism or reproductive parasitism explain patterns of distribution?

“…Accordingly, our understanding of the hybrid's niche may be most effectively studied by examining niche parameters of its progenitors, since these attributes should fundamentally drive hybrid niche requirements. Likewise, according to basic tenets of host–parasite theory (Poulin 2006, Filz and Schmitt 2015, Lymbery 2015), obligate parasites should occupy niches that are entirely contained within the host distribution. This prediction is supported across a variety of host–parasite systems (Feldman et al 2017).…”