Life‐history traits and physiological limits of the alpine fly Drosophila nigrosparsa (Diptera: Drosophilidae): A comparative study

Abstract

Interspecific variation in life‐history traits and physiological limits can be linked to the environmental conditions species experience, including climatic conditions. As alpine environments are particularly vulnerable under climate change, we focus on the montane‐alpine fly Drosophila nigrosparsa. Here, we characterized some of its life‐history traits and physiological limits and compared these with those of other drosophilids, namely Drosophila hydei, Drosophila melanogaster, and Drosophila obscura. We assayed oviposition rate, longevity, productivity, development time, larval competitiveness, starvation resistance, and heat and cold tolerance. Compared with the other species assayed, D. nigrosparsa is less fecund, relatively long‐living, starvation susceptible, cold adapted, and surprisingly well heat adapted. These life‐history characteristics provide insights into invertebrate adaptations to alpine conditions which may evolve under ongoing climate change.

Wolbachiaaffect behavior and possibly reproductive compatibility but not thermoresistance, fecundity, and morphology in a novel transinfected host,Drosophila nigrosparsa

“…Here, we conclude that infection with Wolbachia wMel did not increase heat 387 and cold tolerance in D. nigrosparsa. Wolbachia-infected and Wolbachia-free D. nigrosparsa 388 responded to knockdown temperature at around 38 °C like in an earlier study of this fly species 389 (Kinzner et al, 2018). Thus, we cannot expect a rescue from heat stress due to infection by the 390…”

“…Critical-temperature experiments were modified from Kinzner et al (2018). In Generation 19, seven-149 day old female flies of infected (ni_3, ni_6, and ni_8), cured (nc_3, nc_6, and nc_8), and uninfected 150 8 (nu_0) lines were used.…”

“…Our study indicated that D. nigrosparsa could be a host for Wolbachia like Drosophila melanogaster, 417 the native host of Wolbachia wMel, because vertical transmission is possible in this species. On the 418 long term, the transmission of Wolbachia in D. melanogaster may be better than in D. nigrosparsa 419 because D. melanogaster has a higher oviposition rate and a better tolerance of warm temperatures 420 than D. nigrosparsa (Kinzner et al, 2018), both of which could increase the chance for horizontal 421 transfer. This is because horizontal transfer is a stochastic event, and an infected host is therefore 422 more likely to transfer Wolbachia to a new host species if there are more infected hosts available and 423 if the number of Wolbachia cells is higher per host.…”

Wolbachia affect behavior and possibly reproductive compatibility but not thermoresistance, fecundity, and morphology in a novel transinfected host, Drosophila nigrosparsa

“…Under simulated conditions of alpine summer, these flies have around 60 days of development time from embryos to adults (Kinzner et al, 2016). Several life history traits and physiological limits of D. nigrosparsa have been studied before (Kinzner et al, 2016, 2018; Tratter Kinzner et al, 2019). Drosophila nigrosparsa is less fecund and relatively long living compared with other Drosophila species, and it is well adapted to current cold and hot temperatures (Kinzner et al, 2018).…”

Differential gene expression inDrosophila melanogasterandD. nigrosparsainfected with the sameWolbachiastrain

“…Drosophila (Drosophila) nigrosparsa is an alpine species found at around 2000 m above sea level in Central and Western Europe (Bächli et al ., 2004). Due to the habitat specificity of D. nigrosparsa , molecular and physiological traits and potential effects of warming temperatures on this species have been studied (Arthofer et al ., 2015; Kinzner et al ., 2016, 2018, 2019; Cicconardi et al ., 2017; Tratter Kinzner et al ., 2019). Wild populations of D. melanogaster are commonly infected with Wolbachia (Verspoor and Haddrill, 2011), while no wild population of D. nigrosparsa infected with Wolbachia has been found to date (M. Detcharoen, unpubl.).…”