Quantifying species traits related to oviposition behavior and offspring survival in two important disease vectors

Abstract

Animals with complex life cycles have traits related to oviposition and juvenile survival that can respond to environmental factors in similar or dissimilar ways. We examined the preference-performance hypothesis (PPH), which states that females lacking parental care select juvenile habitats that maximize fitness, for two ubiquitous mosquito species, Aedes albopictus and Culex quinquefasciatus. Specifically, we examined if environmental factors known to affect larval abundance patterns in the field played a role in the PPH for these species. We first identified important environmental factors from a field survey that predicted larvae across different spatial scales. We then performed two experiments, the first testing the independent responses of oviposition and larval survival to these environmental factors, followed by a combined experiment where initial oviposition decisions were allowed to affect larval life history measures. We used path analysis for this last experiment to determine important links among factors in explaining egg numbers, larval mass, development time, and survival. For separate trials, Aedes albopictus displayed congruence between oviposition and larval survival, however C. quinquefasciatus did not. For the combined experiment path analysis suggested neither species completely fit predictions of the PPH, with density dependent effects of initial egg number on juvenile performance in A. albopictus. For these species the consequences of female oviposition choices on larval performance do not appear to fit expectations of the PPH.

Fig 1. Results (raw means ± SE, dashed for survival, solid for oviposition) from separate experiments examining how environmental factors affect oviposition responses (n = 4 replicates) and larval survival (n = 3 replicates) of Aedes albopictus.

A. Response to different water volumes in tires, and B. response to different quantities of pine needle detritus.

Fig 2. Results (raw means ± SE, dashed for survival, solid for oviposition) from separate experiments examining how environmental factors affect oviposition responses (n = 4 replicates) and larval survival (n = 3 replicates) of Culex quinquefasciatus.

A. Response to different water volumes in tires, and B. response to different light levels (higher values of LUX are brighter). Means that share a letter are not significantly different at P = 0.05.

Fig 3. Final path models testing the effect of environmental factors acting as ecological filters on oviposition and larval traits.

A. Model for Culex quinquefasciatus and B. Model for Aedes albopictus. Values for R² are provided next to each variable along with path coefficients next to each path.

Fig 4. Proposed path diagrams testing the effect of environmental factors (Var₁, Var₂) acting as ecological filters on oviposition (eggs) and larval traits (survival, development time, mass).

A. Combined/Full model with all links present. B Larval model: no direct links from filters to egg number. C. Oviposition model: no direct links from filters to larval traits.