A trade‐off between quantity and quality of offspring in haematophagous ectoparasites: the effect of the level of specialization

Abstract

Summary 1.Theory predicts an adaptive trade-off between quantity and quality of offspring if mothers can reliably predict the offspring environment. 2. We studied egg production and quality of offspring in two flea species (host-specialist Parapulex chephrenis and host-generalist Xenopsylla ramesis) exploiting eight rodent species. We evaluated quality of new imagoes via their developmental time, size (length of a femur as a proxy) and resistance to starvation without a blood meal. 3. We predicted that the offspring quality would increase with (i) a decrease in the number of eggs produced by mothers and (ii) an increase in phylogenetic distance between maternal host and principal host of a flea. We also predicted that negative relationships between offspring quality and either maternal egg production effort or phylogenetic distance between maternal host and the principal host or both would be manifested stronger in host-opportunistic than in host-specific fleas. 4. The highest number of eggs produced per female flea was accompanied by the longest duration of development and the smallest offspring in X. ramesis, while P. chephrenis that hatched from larger clutches survived for less time under starvation. Although there was no significant effect of host species on any dependent variable, association between offspring quality and phylogenetic distance of the maternal host from the principal host of a flea was found in X. ramesis (but not P. chephrenis) with new imagoes being larger if their maternal hosts were phylogenetically distant from the principal host. 5. Our results demonstrated stronger trade-off between quantity and quality of offspring in a generalist than in a specialist flea, supporting the association between life-history plasticity and generalist feeding strategy.

Reproductive consequences of female size in haematophagous ectoparasites

“…fluctuations in microclimate or host availability; Berger et al, 2008Berger et al, , 2012. Although a trade-off between the number of eggs and the size of new imagoes in X. ramesis was demonstrated in earlier experiments (Khokhlova et al, 2014), we did not find any trade-off between the number and size of eggs in the current study. On the contrary, in one of the three flea species (X. ramesis), larger clutches were composed of larger eggs.…”

“…Our recent evidence supported a trade-off between the quantity and quality of the offspring in fleas when they exploit different host species (Khokhlova et al, 2014). However, this earlier study estimated the number of the offspring via the number of eggs but estimated offspring quality via size of the new imagoes and rate of their pre-imaginal development.…”

“…Starting from the 18th day after an egg was produced (approximately 1 week before metamorphosis; e.g. Khokhlova et al, 2014), we checked each vial daily until a new imago emerged or, in the case that a new imago did not emerge, for 30 consecutive days after the first new imago in each treatment emerged. Upon emergence, a new imago was killed by placing it into 70% ethanol.…”

“…In this study, we measured the size of each egg directly. In addition, Khokhlova et al (2014) compared the number of eggs among fleas feeding on different host species and thus the quality and quantity of the feeding resource differed among fleas. It remained unclear whether the trade-off between the quantity and quality of offspring occurs when resources are equal among females such as when they feed not only on the same host species but also on the same host individual at the same time.…”

Morphological asymmetry and habitat quality: using fleas and their rodent hosts as a novel experimental system

“…Thus, the environmental quality a parasite experiences could be related to the physiological and/or immunological processes of the host. Novel host species, especially ones distantly related to the principal host species, could represent a lower quality resource for a given parasite (Khokhlova et al, 2014) and thus increase the developmental instability of the parasites forced to utilize them. Co-evolution, host switching and host specificity all focus on evolutionary relationships between hosts and parasites (Combes, 2001;Poulin, 2011).…”