Egg size-number trade-off and a decline in oviposition site choice quality: Female Pararge aegeria butterflies pay a cost of having males present at oviposition

Abstract

Once mated, the optimal strategy for females of the monandrous butterfly, Pararge aegeria, is to avoid male contact and devote as much time as possible to ovipositing, as there is little advantage for females to engage in multiple matings. In other butterfly species the presence of males during egg laying has been shown to affect aspects of oviposition behavior and it has been suggested that repeated interference from males has the potential to reduce reproductive output. The aim of this study was to assess the effects of male presence during oviposition on reproductive output and behavior of a population of P. aegeria obtained from Madeira Island, Portugal, and maintained in the laboratory. Two experiments were performed where females were housed individually in small cages. Experiment 1 examined how social factors influenced the egg laying behavior of females. To do this the presence or absence of males was manipulated and egg size and number was measured over the first 14 days of oviposition. It was observed that when males were present during oviposition females made a trade-off between egg size and number. Experiment 2 examined how social factors affected oviposition site choice. Again, male presence/absence was manipulated, but in this experiment where the female laid her egg in relation to host quality was scored, and the size of the egg laid was measured. In the absence of males females selectively positioned their larger eggs on good quality host plants. However, selective oviposition was no longer observed when females were in the presence of males. We suggest that P. aegeria females from the Madeira Island population are adapted for a flexible oviposition strategy, governed by external cues, allowing a trade-off between egg size and number when the time available for egg laying is limiting.

What Keeps Insects Small? Time Limitation during Oviposition Reduces the Fecundity Benefit of Female Size in a Butterfly

“…It is clear that ambient temperature is not the only factor that may limit oviposition opportunities, and the same reasoning can be applied to other ecological factors, such as predator presence, host availability (Sevenster et al 1998;Ellers et al 2000;Rosenheim et al 2000), and male harassment (Gibbs et al 2005). In the experiments reported here, there was always a host available as soon as temperatures allowed oviposition, and this is obviously an unrealistic scenario.…”

The association between wing morphology and dispersal is sex-specific in the glanville fritillary butterfly Melitaea cinxia (Lepidoptera: Nymphalidae)

“…In general, dispersal in butterflies is very much associated with the availability of both suitable oviposition sites and/or mates. These two factors depend largely on population density (Baguette & Neve, 1994;Baguette et al, 1996), degree of habitat fragmentation, host plant preference, quality and abundance (Saccheri et al, 1998;Hanski, 1999;Van Nouhuys & Hanski, 1999;Hanski & Ovaskainen, 2000;Kuussaari et al, 2000;Hanski et al, 2000Hanski et al, , 2002, the time available for oviposition, as well as the size and number of eggs that females lay on individual host plants (Nylin & Janz, 1996;Kuussaari et al, 2000;Nylin et al, 2000;Hanski et al, 2002;Singer & Hanski, 2004;Gibbs et al, 2005). Furthermore, variation in dispersal is often sex-specific with males and females having different life-history strategies associated with flight and dispersal, while both sexes are often also being differently affected by environmental variation (Van Dyck & Wiklund, 2002;Gibbs & Breuker, 2006).…”

“…Furthermore, variation in dispersal is often sex-specific with males and females having different life-history strategies associated with flight and dispersal, while both sexes are often also being differently affected by environmental variation (Van Dyck & Wiklund, 2002;Gibbs & Breuker, 2006). Females are usually the more dispersive of the two sexes as they need to fly around, often for extended periods of time, to find suitable oviposition sites or to avoid harassment by males (Baguette & Neve, 1994;Baguette et al, 1996;Gibbs et al, 2004Gibbs et al, , 2005.…”

Pleiotropic effects associated with an allele enabling the flea beetle Phyllotreta nemorum to use Barbarea vulgaris as a host plant

“…A possible explanation for this may be that, upon receiving cues of a stressful environment, female insects lay many (small) eggs at the start of oviposition to increase fecundity (Gibbs et al 2005;Gibbs and Breuker 2006). These cues may be received and have an effect at any time from the early stages of development through to adulthood.…”