Generation time and maximum population growth rate
Short generation times enable rapid evolutionary responses (Lynch and
Lande 1993, Bürger and Lynch 1995), and high intrinsic population growth
rates reduce the chance of extinction prior to adaptation (Bürger and
Lynch 1995, Orr and Unckless 2008, Gomulkiewicz and Houle 2009). The
generally rapid life cycles and large population sizes of mosquitoes
favor rapid evolution, but precise demographic estimates under natural
conditions are unavailable for most species (but see Appendix C: Table
S2) and will vary with biotic and abiotic conditions. However, even high
estimates of mosquito lifespans of approximately three months (Macdonald
1952, Nayar and Sauerlllan 1971, Papadopoulos et al. 2016, Joubert et
al. 2016) are on par with or well below those of other species that have
already demonstrated evolutionary responses to climate change
(Rodríguez-Trelles and Rodríguez 1998, Réale et al. 2003, Balanyá et al.
2006, Franks et al. 2007, Gienapp et al. 2007, Ożgo and Schilthuizen
2012, Kovach et al. 2012). Further, high intrinsic population growth
rates (r) of 0.19 – 0.38 per generation have been calculated for
several major vector species (Appendix C: Table S2, Figure S1;
Amarasekare and Savage 2012, Johnson et al. 2015, Mordecai et al. 2017,
Shocket et al. 2020) and census population size estimates on the order
of 1,000 - 10,000 individuals have been found across studies of varying
mosquito species and settings (Touré et al. 1998, Lehmann et al. 1998,
Maciel-de-Freitas et al. 2008, Neira et al. 2014, Le Goff et al. 2019).
Placing these mosquito results in context, a Drosophila modeling
study showed that growth rates and population sizes in this range
facilitated population persistence for over 300 generations under
heat-knockdown selection (Willi and Hoffmann 2009). Mosquito demographic
characteristics therefore favor thermal adaptation.