Analysis of the Mediterranean fruit fly [Ceratitis capitata (Wiedemann)] spatio-temporal distribution in relation to sex and female mating status for precision IPM

Abstract

The Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann), is a key pest of fruit crops in many tropical, subtropical and mild temperate areas worldwide. The economic importance of this fruit fly is increasing due to its invasion of new geographical areas. Efficient control and eradication efforts require adequate information regarding C. capitata adults in relation to environmental and physiological cues. This would allow effective characterisation of the population spatio-temporal dynamic of the C. capitata population at both the orchard level and the area-wide landscape.The aim of this study was to analyse population patterns of adult medflies caught using two trapping systems in a peach orchard located in central Italy. They were differentiated by adult sex (males or females) and mating status of females (unmated or mated females) to determine the spatio-temporal dynamic and evaluate the effect of cultivar and chemical treatments on trap catches. Female mating status was assessed by spermathecal dissection and a blind test was carried out to evaluate the reliability of the technique. Geostatistical methods, variogram and kriging, were used to produce distributional maps. Results showed a strong correlation between the distribution of males and unmated females, whereas males versus mated females and unmated females versus mated females showed a lower correlation. Both cultivar and chemical treatments had significant effects on trap catches, showing associations with sex and female mating status. Medfly adults showed aggregated distributions in the experimental field, but hot spots locations varied. The spatial pattern of unmated females reflected that of males, whereas mated females were largely distributed around ripening or ripe fruit. The results give relevant insights into pest management. Mated females may be distributed differently to unmated females and the identification of male hot spots through monitoring would allow localisation of virgin female populations. Based on our results, a more precise IPM strategy, coupled with effective sanitation practices, could represent a more effective approach to medfly control.

Ecology of female mating failure/lifelong virginity: a review of causal mechanisms in insects and arachnids

“…Theoretical models predicting outcomes of mating interactions relative to emergence time (Morbey & Ydenberg, ) have met diverse empirical observations: female mating probability may be higher in early, middle, or late phases of emergence cycles. In many instances, low female mating probability on a given day coincides with rarity of males (Calabrese & Fagan, ; Franco et al., ; Calabrese et al., ; Rhainds, ; Fauvergue, ; Faust & Forrest, ; Sciarretta et al., ). These studies support widely held views of female‐biased sex ratios and/or acute shortage of males (‘male vacuum’) as triggers of FMF (Wing, ; Mendel et al., ; Fritzsche et al., ).…”

“…Natural mating disruption (high rates of FMF on crowded host plants) can arise due to: (1) males being unable to discriminate receptive females from conspecific males or non receptive females (Richerson et al, 1976;Takeuchi, 2017;Sales et al, 2018), (2) passive olfactory signals of post reproductive conspecifics interfering with mate location (Gwynne & Lorch, 2013;Rhainds, 2018), or (3) adsorption of pheromone onto the foliage of host plants (Noldus et al, 1991). Testing these hypotheses requires small-scale mapping of female mating probability among georeferenced plants (van Wijk et al, 2017;Muniz et al, 2018;Sciarretta et al, 2018).…”

Defining and Evaluating a Decision Support System (DSS) for the Precise Pest Management of the Mediterranean Fruit Fly, Ceratitis capitata, at the Farm Level

“…This approach increased the possibility to perform unnecessary treatments, especially when repeated low catches were found in most traps. Due to this extra cautious approach, only 23% of the DSS spraying recommendations reported a capture aggregation, even though it has been reported that medfly in this area and elsewhere tends to significantly aggregate, especially under low population densities [26,27]. Even with these limitations, the application of the DSS algorithm allowed us to differentiate insecticide applications for each cultivar, resulting in precision targeting treatments.…”

Mapping the spatial variability of the field distribution of sterile Anastrepha ludens over a release area

“…Geospatial tools provide a greater understanding of the pest dynamics and its spatial relationships with a surrounding environment (Ellsbury et al, ; Fleischer, Blom, & Weisz, ; Liebhold, Rossi, & Kemp, ). More recently, the modelling of the spatial behaviour of pest species of Tephritidae such as A. ludens, Bactrocera oleae Rossi and C. capitata incorporated GIS and geostatistics applications (Castrignanò et al, ; Papadopoulos, Plant, & Carey, ; Sciarretta et al, ; Vanoye‐Eligio, Barrientos‐Lozano, Pérez‐Castañeda, Gaona‐García, & Lara‐Villalon, ). Moreover, the analysis of spatio‐temporal patterns of adult captures has become a technical base for conducting specific strategies against the Medfly, C. capitata , over the last years (Cohen et al, ; Enkerlin et al, ; Midgarden, Lira, & Silver, ).…”