John Abraham

The rapid geographical expansion of D. suzukii and its severe impact on fruit production have prompted extensive research into its behavior (e.g., Abraham et al., 2015;Revadi et al., 2015;Cloonan et al., 2018;Larson et al., 2021) and motivated the first volume of the Research Topic, "Research Advances on Drosophila suzukii" (Abraham et al., 2022). That volume included studies of feeding behavior (Kraft et al., 2021) and oviposition behavior (Stockton & Loeb, 2022). It also presented a non-destructive, high-throughput DNA metabarcoding method to detect D. suzukii and discriminate it from its closest relatives and other non-target arthropods in large, unsorted trap catches (Piper et al., 2022). Following this, Piñero et al. (2022) demonstrated that diluted Concord grape juice can be as attractive, or in some cases more attractive than, commercial attractants meant for monitoring traps. Similarly, it has also been proven that synthetic blends of fruit volatile compounds are attractive to both female and male D. suzukii (Bolton et al., 2022). This finding is in line with our earlier study (Abraham et al. 2015). To improve attract-and-kill strategies for D. suzukii, Babu et al. (2022) identified fenpropathrin, cyantraniliprole, malathion, zeta-cypermethrin, and spinosad as insecticides that could be combined with ACTTRA SWD® in attract-and-kill formulations for the effective management of this pest.The present Research Topic builds on these advances through three complementary contributions addressing the genomic basis of adaptation, geographical variation in the microbiome, and behaviour-based pest management. In their bid to fully understand the behavior of D. suzukii, Berrutti et al. characterized the distribution and potential impact of transposable elements (TEs) within and near cytochrome P450 monooxygenase (CYP) genes in D. suzukii and compared their distribution with that observed in its non-pest relative, Drosophila melanogaster. They identified ten duplicated CYP genes unique to D. suzukii and found that these duplications were enriched in TE fragments, particularly Helitrons. Their results suggest that increased TE content may have enhanced genomic plasticity, thereby facilitating the species' invasive success, rapid population growth, and ability to adapt to diverse habitats, including native environments and agricultural fields.Drosophila suzukii continues to expand its range (de la Vega et al., 2020;Boughdad et al., 2021;Kwadha et al., 2021) and there is the potential for further expansion (Maino et al., 2021;Abeijon et al., 2025). However, the adaption of D. suzukii to new territories is gradually being linked to the microbes associated with their hosts. It is thought that these microbes could play a role in the adaptation of D. suzukii by improving host resilience to environmental stress. To examine whether the colonization of new regions by D. suzukii is associated with changes in its microbiome, Medeiros et al. compared the microbiome profiles of wild-caught D. suzukii from five geographical regions: Asia, continental Europe, the United Kingdom, North America, and Hawai'i. They also compared the microbial communities of D. suzukii found in Hawai'i with those of the non-native Drosophila immigrans, and native Hawaiian drosophilids. Their findings showed that wild-caught D. suzukii from the five regions had distinct microbial compositions indicating that the geographical environment may be a stronger driver of microbiome composition than species identity. The results indicate that D. suzukii may retain a core set of bacterial families while acquiring or enriching locally available microbial taxa after colonizing a new habitat. However, whether these microbiome changes confer adaptive advantages, such as access to new dietary resources, remains to be determined.Cruz-Esteban reviewed the management of D. suzukii by exploiting its behavior, an approach commonly referred to as ethological control. Several earlier studies have delved into this (e.g., Abraham et al., 2015;Cloonan et al., 2018). However, the current review by Cruz-Esteban synthesizes recent advances involving olfactory attractants, visual stimuli, trap density and spacing for mass trapping, and push-pull systems that incorporate oviposition deterrents.Together, the contributions to this Research Topic illustrate the value of integrating genomic, microbial, and behavioral perspectives to improve our understanding of the invasion biology of D. suzukii. They also highlight promising directions for developing more effective and environmentally sustainable management strategies for this insect pest in soft-fruit production systems.

The tendency of parasitoid wasps to oviposit in a previously parasitised host (superparasitism) has long been considered detrimental to their fitness, until recent evidence showed that it may be an adaptive strategy. The solitary koinobiont parasitoid, Coccygidium luteum, was observed to superparasitise the fall armyworm, Spodoptera frugiperda, under laboratory conditions. This study was conducted to elucidate the oviposition choice between unparasitised and previously parasitised hosts by C. luteum and to determine the effect of superparasitism on progeny development and adult fitness, using fall armyworm larvae as hosts. In a choice assay, previously parasitised and unparasitised hosts were simultaneously exposed to C. luteum for oviposition. Oviposition duration and preference were observed and the influence of superparasitism on the development of immature parasitoids and adult fitness were investigated by exposing host larvae to single, double and triple parasitism at 1 h intervals. Coccygidium luteum readily attacked both unparasitised and previously parasitised hosts without discrimination. However, the time spent ovipositing on the unparasitised host was significantly longer than that on a previously parasitised host. Superparasitism did not significantly affect progeny development and the fitness of adult C. luteum. Offspring development time and size of adult parasitoids were similar in superparasitised hosts compared to hosts that were parasitised once. We conclude that superparasitism in C. luteum will have no effect on its mass rearing for the biological control of S. frugiperda.

Urbanisation continues to increase at an alarming rate and its effects on the natural environment are very profound now more than ever. Moreover, studies on terrestrial urban landscapes seems to be more than that on urban freshwater habitats. Furthermore, studies have shown that the Odonata are effective indicators of the effects of urbanisation on freshwater habitats. However, not much is known about their responses to urbanisation in sub‐Saharan Africa, especially given the unique set of conditions that characterise the area. Therefore, this study was conducted to investigate differences in Odonata responses, measured as the proportion of habitat generalists, to three levels of habitat disturbance in the Cape Coast Metropolis of Ghana. Results showed that Phaon camerunensis was a potential indicator of habitat disturbance. Also, differences in habitat disturbance significantly affected Odonata composition. The most important variables that influenced Odonata responses were the individual and interaction effects of altitude and preservation of riparian vegetation. Therefore, conservation strategies that are targeted at reducing the impacts of urbanisation on Odonata must focus on these variables.

Mass trapping of insects involves the use of specific traps or devices that are designed to attract and capture a large number of adult insects, thereby reducing their population in the agricultural environment. This approach aims at disrupting the breeding cycle and proliferation of the target insect to minimize crop damage and economic losses. This study evaluated the efficiency of three trap types (Ecoman, Tephri, and Bucket funnel) and period of the day (morning, afternoon, and evening) in mass trapping of live male Bactrocera dorsalis and the survival of such catch over a period. The traps were deployed on selected trees following 33 factorial experiments. All the Bactrocera dorsalis caught in the traps were males. Ecoman traps caught the highest number of B. dorsalis in the mornings and evenings while Tephri traps caught the highest B. dorsalis in the afternoons. There was no significant difference in the survival of B. dorsalis in the three trap types after 24hours. Correlation analysis showed that climatic factors played a significant role in trap catches. Bactrocera dorsalis caught in the evenings recorded higher percentage survival in all the three trap types than those caught during the morning and afternoon. The Ecoman trap was most efficient in trapping B. dorsalis. Hence, this study recommends the Ecoman trap for mass trapping live male B. dorsalis meant for further experiments such as irradiation studies.

The life cycle of the invasive alien insect pest, fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), was studied using a colony established from field-collected larvae. Eggs, neonate larvae, and newly emerged adult moths were used in experiments to investigate the basic biology of the FAW. Adult females laid up to 1184 eggs with a mean of 46922 eggs per female. The incubation period of eggs and percentage hatchability were 2-3days and 8087, respectively. The mean larval lengths from the first to the sixth instar were 4.63, 6.60, 9.76, 15.86, 25.13, and 27.81mm, respectively. The mean larval weights were 0.003, 0.019, 0.045, 0.050, 0.060, and 0.067g, respectively, for the six instars. The mean width of the head capsule of the sixth instar larva was 2.76mm. The total larval duration throughout the six instar stages was 1618days, while the mean pupal weight was 0.250.001g and 0.350.011g for males and females, respectively. The mean pupal length was 14.30.16mm for males and 17.20.14mm for females. Pupal duration ranged from 8 to 14days, with a mean of 10.350.26days, while the pupal emergence rate ranged from 60 to 94, with a mean of 80.251.28. The life cycle of males lasted 3344days and that of females lasted 3649days under laboratory conditions. Adult copulation occurred between 8 and 11 pm, with the peak occurring at 9 pm. This study provides baseline information about the biology of the FAW. Apart from being an important reference point for future research on the FAW, the data provided would aid FAW management decision-making.

Tephritid fruit flies, including Ceratitis ditissima, often invade citrus orchards. These flies cause economic losses to farmers and can prevent farmers from exporting their fruits to foreign markets. To detect the presence of fruit flies in citrus orchards, traps are baited with synthetic lures, which are often expensive for smallholder farmers. Farmers in developing or financially less-endowed countries have to import such synthetic baits, raising the cost of pest monitoring and control. Therefore, we evaluated the potential of palm wine and three other food-based mixtures for trapping C. ditissima and the proportion of non-target flies they trap. Transparent deli cup traps were baited with four different food-based baits, namely palm wine, sugarcane spirit-wine mixture, apple cider vinegar and yeast-sugar mixture. The traps were placed within a citrus orchard on fruit-bearing trees. The content of each trap was collected after one week and evaluated. This was repeated for eight consecutive weeks. Traps baited with palm wine captured more C. ditissima than those with the other baits. Furthermore, the proportion of non-target insects, Bactrocera dorsalis and Drosophila spp., in palm wine-baited traps was less than the other baited traps. This study indicates that palm wine, a cheap beverage across Africa, Asia and South America, could be used to monitor the presence of C. ditissima in citrus orchards. Smallholder farmers who cannot afford expensive synthetic baits could make use of palm wine to monitor fruit flies in their farms.

Editorial: Research Advances on Drosophila suzukii