Is Polyandry a Common Event Among Wild Populations of the Pest <I>Ceratitis capitata</I>?

Abstract

In many insect species, females can mate more than once and store sperm from more than one male. An assessment and understanding of polyandry in the field can be important for pest species with a high colonization potential, such as the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), which is also highly polyphagous and among the most destructive agricultural insects. The use of polymorphic microsatellite markers, combined with different statistical approaches, provides evidence that polyandry occurs in two C. capitata natural populations, one population from the Greek island of Chios and one population from Rehovot, in Israel. The observed different level of polyandry is discussed in relation to the genetic diversity, seasonality, and demography of the two populations. When polyandry is present, paternity analysis also indicates that one male, presumably the last, tends to sire most of the progeny. Polyandry and paternity skew may have important implications for the evolution of the species, in terms of maintenance of the genetic variability. Moreover, these aspects of the mating behavior, i.e., remating frequency and paternity skew, may locally affect the sterile insect technique, the most commonly applied control strategy against C. capitata.

On the impact of re-mating and residual fertility on the Sterile Insect Technique efficacy: Case study with the medfly, Ceratitis capitata

“…Some field studies reported percentages of double mating in wild females: up to 50% [ 34 ]; less than 28% [ 35 ]; 4% to 28% [ 67 ]. Laboratory tests reported by Abraham et al [ 31 ] indicated 20% re-mating for females mated with 100Gy-irradiated males.…”

“…This parameter has been repeatedly studied in the laboratory with various estimates. However, analysis of field-sampled females progeny showed less than 28% [ 35 ] or 50% [ 34 ] multiple mating. It is thus possible to roughly estimate a percentage of female daily re-mating proportion: in average, between 7% and 12%.…”

“…However, the fertilization chamber in medflies allows a second male to remove sperm from the previous one [41]. Sperm precedence of the second male mating a female tends to succeed in fertilizing eggs (second male contribution greater than 0.5) [34,39,[42][43][44]. In [45], the authors studied doublemated females and show how the sperm of the first and the second mating are stored, meaning that both are able to be used to fertilize the eggs.…”

“…Female medflies are facultatively polyandrous [ 34 , 35 ]. After mating, medfly females typically exhibit an average refractory period of two and a half days [ 36 ].…”