Reproductive Flexibility: Genetic Variation, Genetic Costs and Long-Term Evolution in a Collembola

Abstract

In a variable yet predictable world, organisms may use environmental cues to make adaptive adjustments to their phenotype. Such phenotypic flexibility is expected commonly to evolve in life history traits, which are closely tied to Darwinian fitness. Yet adaptive life history flexibility remains poorly documented. Here we introduce the collembolan Folsomia candida, a soil-dweller, parthenogenetic (all-female) microarthropod, as a model organism to study the phenotypic expression, genetic variation, fitness consequences and long-term evolution of life history flexibility. We demonstrate that collembola have a remarkable adaptive ability for adjusting their reproductive phenotype: when transferred from harsh to good conditions (in terms of food ration and crowding), a mother can fine-tune the number and the size of her eggs from one clutch to the next. The comparative analysis of eleven clonal populations of worldwide origins reveals (i) genetic variation in mean egg size under both good and bad conditions; (ii) no genetic variation in egg size flexibility, consistent with convergent evolution to a common physiological limit; (iii) genetic variation of both mean reproductive investment and reproductive investment flexibility, associated with a reversal of the genetic correlation between egg size and clutch size between environmental conditions ; (iv) a negative genetic correlation between reproductive investment flexibility and adult lifespan. Phylogenetic reconstruction shows that two life history strategies, called HIFLEX and LOFLEX, evolved early in evolutionary history. HIFLEX includes six of our 11 clones, and is characterized by large mean egg size and reproductive investment, high reproductive investment flexibility, and low adult survival. LOFLEX (the other five clones) has small mean egg size and low reproductive investment, low reproductive investment flexibility, and high adult survival. The divergence of HIFLEX and LOFLEX could represent different adaptations to environments differing in mean quality and variability, or indicate that a genetic polymorphism of reproductive investment reaction norms has evolved under a physiological tradeoff between reproductive investment flexibility and adult lifespan.

Ecological changes in historically polluted soils: Metal(loid) bioaccumulation in microarthropods and their impact on community structure

“…For each springtail species, species code, feeding traits (sucker/shredder), reproduction traits (standard, standard-to-explosive, explosive, parthenogenesis), vertical distribution according to Gisin (1943), and total count in the soil samples are shown in Table 3 (Hopkin, 1997). The determining of springtail reproduction modes was performed from work of Czarnetzki and Tebbe (2004) and Tully and Ferriere (2008). The diet of springtails (sucker/shredder) was defined from the shape of the mouthparts notably maxillar (Chen et al, 1997;Santorufo et al, 2014aSantorufo et al, , 2014bHoskins et al, 2015).…”

Long-Term Consumption and Food Replacement of Near-Isogenic by Bt-Maize Alter Life-History Traits of Folsomia Candida Willem 1902 (Collembola)

“…Probably, as a consequence of accommodation to food, our collembolans in BtBt treatment produced larger eggs than in IsoIso one. Tully and Ferrière (2008) found that there is a positive relationship between egg size and juvenile size, and larger F. candida juveniles have improved quality, which means a higher chance to survive and better productivity. Maybe that is why the time until the first http://www.aloki.hu • clutch is shorter (although not significantly) and the body growth rate is higher in BtBt treatment and BtBt collembolans reach their maturity earlier.…”

The influence of different substrates on the reproduction traits of Folsomia candida (Collembola) in an insecticide test

“…From the ecotoxicological point of view, the egg number decreases due to the effect of heavy metal contamination (Fountain and Hopkin, 2001;Smit et al, 2004). If evolution biology of F. candida was in the focus of the study, difference between clonal lines (Stam, Leemkule and Ernsting, 1996), life-history traits (Tully and Ferrière, 2008;Hafer et al, 2011), or Wolbachia symbiont presence (Timmermans and Ellers, 2009) were studied. Other parameters as the egg shape, the egg viability, and the egg size are rather involved in ecological and evolution biological studies not in ecotoxicological ones (Stam, Leemkule and Ernsting, 1996;Tully and Ferrière, 2008;Timmermans and Ellers, 2009;Hafer and Pike, 2010;Hafer et al, 2011).…”

“…If evolution biology of F. candida was in the focus of the study, difference between clonal lines (Stam, Leemkule and Ernsting, 1996), life-history traits (Tully and Ferrière, 2008;Hafer et al, 2011), or Wolbachia symbiont presence (Timmermans and Ellers, 2009) were studied. Other parameters as the egg shape, the egg viability, and the egg size are rather involved in ecological and evolution biological studies not in ecotoxicological ones (Stam, Leemkule and Ernsting, 1996;Tully and Ferrière, 2008;Timmermans and Ellers, 2009;Hafer and Pike, 2010;Hafer et al, 2011). For example, Tully and Ferrière (2008) measured egg size, egg number, clutch size and clutch number to reveal the different life-history strategies of F. candida reacting to different food availability and overcrowding.…”

“…Other parameters as the egg shape, the egg viability, and the egg size are rather involved in ecological and evolution biological studies not in ecotoxicological ones (Stam, Leemkule and Ernsting, 1996;Tully and Ferrière, 2008;Timmermans and Ellers, 2009;Hafer and Pike, 2010;Hafer et al, 2011). For example, Tully and Ferrière (2008) measured egg size, egg number, clutch size and clutch number to reveal the different life-history strategies of F. candida reacting to different food availability and overcrowding. Another parameter is the growth of animals which is not measurable in experiments carried out in soil only in plaster of Paris.…”