Search Results (106)

The spotted wing drosophila, Drosophila suzukii is an injurious polyphagous pest threatening worldwide soft fruit production. Its high adaptability to new colonized environments, short life cycle, and wide host range are supporting its rapid spread. The most common techniques to reduce its significant economic damage are based on multiple insecticides applications per season, even prior to the harvest, which reduces agroecosystem biodiversity and affects human and animal health. Environmental concerns and regulatory restrictions on insecticide use are driving the need for studies on alternative biological control strategies. This study aimed to assess the effect of T. drosphilae in controlling D. suzukii infestations and its interaction with P. vindemiae, a secondary parasitoid naturally present in Apulia (South Italy). Field experiments were carried out in organic cherry orchards in Gioia del Colle (Bari, Italy) to test the efficacy and adaptability of T. drosphilae following weekly releases of artificially reared individuals. Additionally, the interaction between P. vindemiae and T. drosphilae was studied under laboratory conditions. Results from field experiments showed that D. suzukii populations were significantly lower when both parasitoids were present. However, T. drosophilae was less prone to adaptation, so its presence and parasitism were limited to the post-release period. Laboratory experiments, instead, confirmed the high reduction of D. suzukii populations when both parasitoids are present. However, the co-existence of the two parasitoids resulted in a reduced parasitism rate and offspring production, notably for T. drosophilae. This competitive disadvantage may explain its poor establishment in field conditions. These findings suggest that the field release of the two natural enemies should be carried out with reference to their natural population abundance to not generate competition effects. Full article

Plant–herbivore–parasitoid systems are poorly studied in the tropics. Enicospilus carmenae Campos and Palacio sp. nov. are described, originating from southern Mexico in the Yucatan Peninsula and establishing a new tri-trophic interaction. This species is a koinobiont larval endoparasitoid of the American silkworm moth caterpillar Zanola verago (Cramer) (Lepidoptera: Apatelodidae) feeding on the shrub Piper neesianum C.DC. (Piperaceae) in a semi-evergreen forest. The host plant P. neesianum had no herbivore records to date, and a single collection event yielded the rearing of a new species of Enicospilus (Ichneumonidae, Ophioninae). Morphological, molecular (COI), biological, ecological, and geographical data are integrated to delineate the new species. Full article

Due to the biofactories’ concern for the quality of the parasitoid Cotesia flavipes (Hymenoptera: Braconidae), a common practice is to introduce a population collected from the field into the laboratory mass rearing, even without prior information about the introduced population’s quality or potential positive outcomes. Thus, the objective of this study was to determine whether populations of the C. flavipes parasitoid collected from the field exhibit better biological characteristics and flight activity, with the aim of incorporating them into laboratory mass rearing to enhance the quality of the parasitoids. To achieve this, a population of C. flavipes collected from the field (Pradópolis, SP, Brazil) was studied for twenty generations and compared with a population maintained in the laboratory for 42 years. The egg-to-pupa period in the field population was shorter across generations, particularly in the twentieth generation (11.0 days). Although the field population exhibited a lower number of adults that emerged per host in the fifth and tenth generations, by the twentieth generation, it showed higher offspring production per parasitized host (56.5 parasitoids/host). The results of the flight activity test revealed that both the laboratory-maintained population and the field-collected population exhibited higher percentages of insects classified as walkers compared to flyers (25.7% to 32.3% flying). The field-collected population stabilized in the laboratory by the tenth generation. Moreover, the results of the biological characteristics, longevity, and flight activity of the parasitoids indicate similar quality between the two populations studied after stabilization of the field-collected population. Full article

Trichopria drosophilae is a globally distributed pupal parasitoid that targets various species within the Drosophilidae family, including the invasive Drosophila suzukii. The mass rearing of T. drosophilae is a crucial step in ensuring their successful application for field D. suzukii control. The pupae of Drosophila melanogaster are currently used as a host for the mass rearing of T. drosophilae. After irradiation, the immune system function of Drosophila pupae was weakened, leading to an increase in the parasitism efficiency of the T. drosophilae. Our results showed that irradiated pupae had a significant impact on the parasitism rate, offspring eclosion rate, offspring number, and female body size of F1 T. drosophilae, all of which were significantly lower than those in the normal group. However, there was no significant difference in the parasitism rate, body size, offspring eclosion rate, offspring number, or offspring sex ratio between F2 T. drosophilae emerging from treated or untreated Drosophila pupae. Compared with F2, F1 had a significantly higher net reproductive rate (R₀), mean generation time (T), and doubling time (DT), while the intrinsic rate of increase (r) was significantly lower. Using irradiated D. melanogaster pupae provides an efficient method for the mass rearing of T. drosophilae and offers valuable insights into its potential effectiveness in field D. suzukii control. Full article

Biological control by releasing a large number of parasitoids has been an effective strategy for coping with stored-product pest insects. Habrobracon hebetor (Say) (Hymenoptera: Braconidae) has strong control capabilities over Lepidoptera pests. Exploring the optimum storage temperature, life stage, and cold storage period of H. hebetor is of great importance for the utilization of parasitoids. In this context, the survival, parasitism, and fecundity of H. hebetor were evaluated after 10, 20, 30, 40, 50, and 60 d of exposure at −5, 0, 5, 10, and 15 °C for H. hebetor eggs, larvae, pupae, and adults, and the survival, parasitism, and fecundity of H. hebetor individuals that had been maintained at normal rearing condition were taken as a control. The cold exposure duration dramatically affected the development and survival of eggs, larvae, and pupae of H. hebetor, regardless of the temperatures tested. Habrobracon hebetor eggs, larvae, and pupae failed to develop into the next life stage at −5, 0, and 5 °C. Habrobracon hebetor eggs, larvae, pupae, and adults failed to survive after 10 d exposure at −5 and 0 °C. The parasitism rate, fecundity and oviposition duration of H. hebetor adults that originated from eggs, larvae, pupae, and adults after different cold storage durations markedly decreased with increasing cold storage duration. The highest parasitism rate of adults was 34.12% after exposure at 5 °C for 10 d, which was not significantly different from the control (31.86%). The maximum level of egg production of H. hebetor adults developed from initial larvae exposed at 15 °C for 10 d and 20 d were 344.67 and 340.67 eggs/female, respectively, which were not significantly different from the control (392.00 eggs/female). When H. hebetor larvae were stored at 15 °C for 10 and 60 d, the oviposition duration of newly emerged adults reached the maximum and minimum levels recorded, with 17.00 and 0.83 d, respectively. These results provide empirical support for the large-scale production and storage of H. hebetor. Full article

In China, the Asian corn borer (ACB), Ostrinia furnacalis (Guenee) (Lepidoptera: Pyralidae), is the most significant economic insect pest of corn, causing losses ranging from six to nine million tons annually by feeding on all parts of maize, including damaging ears and leaves and making tunnels in stems. In China, since the 1970s, the Trichogramma species have extensively mass-reared from factitious hosts to control ACB and support integrated pest management programs. The Trichogramma dendrolimi Matsumura and T. ostriniae Pang and Chen are the most efficient biocontrol agents for controlling ACB among the available Trichogramma species. To evaluate the reproductive success of Trichogramma dendrolimi and T. ostriniae, we assessed the impact of varying parasitoid ratios (5:1, 3:1, 1:1, 1:3, and 1:5 representing T. dendrolimi and T. ostriniae, respectively) on adult offspring emergence and mortality from ACB eggs over multiple generations (from first (F₁) to third (F₃) generations). We discovered that both Trichogramma species’ offspring emergence was significantly influenced by the parasitoid generations, parasitoid ratios, and their interactions. The offspring mortality in both Trichogramma species was significantly affected by parasitoid generations but was not significantly influenced by parasitoid ratios or interaction between parasitoid generations and parasitoid ratios. Furthermore, at parasitoid ratios of 5:1, 3:1, and 1:1, the emergence rate of the F₁ generation of T. dendrolimi was significantly higher compared to the ratios of 1:3 and 1:5. However, in the F₂ generation, the emergence of T. dendrolimi decreased considerably, and no emergence was observed in the F₃ generation. A contrasting trend was observed in the emergence of T. ostriniae offspring. Overall, regardless of the parasitoid ratios, the offspring emergence of T. ostriniae in all three generations was significantly higher than that of T. dendrolimi. After assessing the offspring mortality in our research by dissecting the unhatched eggs, we found an inverse relationship between the T. dendrolimi generations and their mortality across different parasitoid ratios. Notably, mortality exhibited a significant decline with an increasing number of generations. A positive correlation was observed between the number of T. ostriniae generations and their mortality across different parasitoid ratios, indicating that mortality increased with successive generations. Overall, across all parasitoid ratios and generations, the offspring mortality of T. ostriniae was considerably greater than that of T. dendrolimi. These results suggest that mortality is a crucial empirical measure that validates T. ostriniae’s superiority over T. dendrolimi. These findings highlight the importance of selecting suitable parasitoid species when implementing Trichogramma for pest management. Full article

In the control of agricultural and forestry pests, excessive reliance on chemical pesticides has led to increasingly severe issues, such as toxic residues and heightened pest resistance. The effective use of biological control has become a major focus in pest management. Parasitoid wasps, as a critical natural enemy of pests, are widely distributed, diverse in species, and play an essential role in natural pest control. Copidosomopsis nacoleiae, a recently discovered polyembryonic endoparasitoid wasp, parasitizes Diaphania angustalis; yet, its biological characteristics remain insufficiently studied. The artificial rearing and population propagation of this wasp have not yet been achieved, and its reproductive behavior and rhythm are not fully understood. To better utilize natural enemy resources and maximize their pest control benefits, we conducted laboratory rearing, behavioral observation, and population surveys to investigate the morphological characteristics, life history, and behavioral patterns of C. nacoleiae. Under laboratory conditions, C. nacoleiae has a generational cycle of 48.71 ± 0.48 days, with an egg–larval period of 32.17 ± 0.20 days and a pupal period of 14.36 ± 0.27 days. Adult wasps require nutritional supplementation and have a maximum lifespan of 2.18 ± 0.09 days when fed 10% honey water. The pre-mating period for adults is 4.72 ± 0.24 h, with an average mating frequency of 5.17 ± 1.65 times per lifetime. Females have a pre-oviposition period of 2.80 ± 0.31 h and an oviposition period of 4.52 ± 0.12 h, laying between 2 and 95 eggs, with an average of 12.75 ± 9.99 eggs, totaling 107.55 ± 28.38 eggs over their lifespan. Offspring production increases with the body length of the host’s mature larvae. Through the successful establishment of a laboratory population of D. angustalis, the biological characteristics, reproductive behavior, and rhythms of C. nacoleiae were systematically examined in this study, and its occurrence dynamics in the field were investigated. These results provide a theoretical foundation for the large-scale propagation and application of C. nacoleiae to control D. angustalis populations effectively. Full article

Asian corn borer (ACB), Ostrinia furnacalis Guenee (Lepidoptera: Crambidae) and the rice moth (RM), Corycyra cephalonica Stainton (Lepidoptera: Pyralidae) are economically significant insect pests that threaten the agricultural products worldwide. Trichogramma parasitoids are successfully mass-reared using artificial host eggs, RM, and are often managed by economically important lepidopterous pests, such as ACB in China. Trichogramma ostriniae Pang and Chen (To) and T. dendrolimi Matsumura (Td) (Hymenoptera: Trichogrammatidae) are two important parasitoids of ACB. To determine the influence of interspecific competition between To and Td on their offspring’s emergence. We determine the emergence of wasp progeny from two distinct hosts (ACB and RM eggs) of varying densities (10, 20, 30, and 100) by examining the effect of three distinct oviposition sequences (To-Td, Td-To, and To+Td) by two Trichogramma species. We discovered that the progeny emergence rate of To and Td from the host was substantially influenced by the parasitoid types, host types, oviposition sequences, and host densities, and their two-, three-, and four-factor interactions while investigating the ACB and RM eggs after oviposition. Additionally, the progeny of Td emerged from 10, 20, and 30 ACB host eggs under three oviposition sequences, which was significantly higher than that of ACB eggs of 100 densities. Nevertheless, the optimum emergence rate of Td progeny was also observed in ACB eggs with a density of 100 under all oviposition sequences. The most suitable oviposition sequences for both wasp species are To-Td and Td-To, as they have the highest rate of progeny emergence. The progeny emergence of both Trichogramma species from RM eggs of varying densities was observed to be significantly different. Nevertheless, the most influential density is 100 RM eggs, as a result of the maximal emergence rate of To and Td. Overall, it is concluded that host eggs with a density of 100 are adequate to meet the oviposition requirements of both wasps in all oviposition orders, thereby limiting their interspecific competition. These findings provide insights into optimizing host density and oviposition strategies for mass-rearing Trichogramma species, which can enhance their efficacy in biological control programs. Future research should explore field-level applications to validate these laboratory findings under natural conditions. Full article

The development of the mass rearing technique for the egg parasitoid Telenomus podisi has been under study for about 20 years, with increasing attention on the development of quality control. Here, we evaluated the behavior, biological parameters, morphometrics and presence of endosymbionts of T. podisi produced in cryopreserved eggs compared to those produced in traditional fresh stink bug eggs. Parasitoids reared from cryopreserved eggs showed similar parasitism and emergence rates, sex ratios, longevity, morphometrics, and proportions of flyers compared to those originating from fresh eggs. Slight differences, including an increase in egg-to-adult development time and differences in the presence of endosymbionts, were observed. Despite these differences, we conclude that the use of cryopreserved eggs is suitable for T. podisi mass rearing, allowing more options for timed inundative parasitoid releases for biological control. Full article

Insect diapause and response to thermal stress are similar in the variety of manifestations. However, the influence of thermal shocks on the incidence of insect diapause has not been sufficiently studied. Our laboratory experiments showed that both cold (−10 °C) and heat (43 °C) shocks experienced for at least 20–30 min significantly reduced the incidence of facultative larval winter diapause in the insect egg parasitoid Trichogramma telengai. However, the patterns of these responses were substantially different. In particular, the peaks of the sensitivity to diapause-averting effects of heat and of cold shocks fell, correspondingly, on middle-stage (5 days of development at 15 °C) and late-stage (9–11 days of development at 15 °C) larvae. Heat shocks influence the incidence of diapause mostly via the changes in the initial proportions of diapause-destined and non-diapause-destined individuals, whereas the effect of cold shocks is mostly based on differential mortality (i.e., the difference in mortality among treatments of the same experiment) with better survival of non-diapause-destined individuals. These results elucidate the peculiarities of the interaction between stress and diapause, allowing us to specify the methods for Trichogramma mass rearing and storage. Full article

We know little about how parasitoids of herbivorous insects use herbivore-induced volatile organic compounds (VOCs) to locate potential hosts on saplings in forests, and how this depends on tree composition. Therefore, we performed an experiment in a forest in Poland where we placed pairs of oak saplings (Quercus robur or Q. petraea) in neighborhoods dominated by oak, beech, or pine trees. We treated one sapling in each pair with the phytohormone methyl jasmonate, which triggers induced responses in plants. We measured the VOC emissions of thirty-six saplings and placed Malaise traps with five of the pairs. We counted the parasitoids in the ten Malaise samples and identified them using DNA metabarcoding. We used parasitoids reared from oak-feeding caterpillars to estimate which species are associated with oaks. The two species of oak differed in both the proportions of VOCs and the specific VOCs that were elevated following the application of methyl jasmonate. We did not detect any overall effects of treatment on parasitoid abundance or community composition. However, some parasitoid species that were associated with oaks appeared to be attracted to elevated emissions of specific induced VOCs. The parasitoid communities differed significantly between sites and showed marginally significant differences between neighborhoods. Overall, our results suggest that parasitoids in the understory are affected by tree composition of the canopy, but the effects of VOC emissions are limited. Full article

Green spaces in urban areas, such as parks and gardens, provide recreational, social, and health benefits for more than half of the world’s inhabitants. Arthropods in urban vegetation may cause some disruption to humans but also provide vital ecological services such as biological control and pollination. However, little is known about the ecology of urban pests, their natural enemies, and how to manage them in an ecofriendly manner, especially in Southern Europe. In this review article, we consider the information available concerning the biological control of aphids in the urban green areas of Spain, mainly focusing on the different aphid species, their natural enemies (and how to enhance them), and the sampling methods used to study them. A wide range of aphid species is found in Spain, but only a few are responsible for the majority of damage (so-called k-aphids, most of which are holocyclic species), and these show two distinct injury profiles (short and long) that determine monitoring and control strategies. Urban aphids have numerous natural enemies, including more than 20 species of ladybeetles, as well as predatory hoverflies, midges, lacewings, bugs, and other groups. More than 40 species of aphid parasitoids and their tritrophic aphid plant associations have been reported. The availability and usefulness of commercially reared aphid natural enemies is discussed, and two methods to enhance natural enemies are described. We also review aphid sampling methods developed for urban green spaces. The studies provide basic information on the ecology of aphids to support conservation biological control as a reliable strategy in the urban green areas of Spain. Full article

Anastatus is the second-largest genus in the family Eupelmidae, with 150 species found worldwide and fourteen known species in China. Most species in this genus are the primary parasitoids of insect eggs, particularly those of Lepidoptera and Hemiptera, and several species have been used for the biological control of various insect pests. In this paper, seven new species of Anastatus Motschulsky, 1859 (Hymenoptera: Eupelmidae) from China are described, of which A. caeruleus Wang and Peng n. sp. and A. garygibsoni Zhou and Peng n. sp. were reared from the eggs of Tessaratoma papillosa (Hemiptera: Tessaratomidae), while A. daiyunensis Wang and Peng n. sp., A. makrysourus Zhou and Peng n. sp., A. polikiarkoudus Wang and Peng n. sp., A. taibaiensis Wang and Peng n. sp., and A. zdenekbouceki Zhou and Peng n. sp. were collected by malaise traps or sweeping. The new species are all described and illustrated based on female specimens, and the key to all 21 Chinese Anastatus species, based on females, is provided. Partial COI sequences of A. caeruleus n. sp., A. garygibsoni n. sp., and A. taibaiensis n. sp. are provided, and a phylogenetic reconstruction based on maximum likelihood analyses, while showing similar results at high taxonomic levels to our morphological feature classification results, provides additional information on the placement of Anastatus at the species level. Full article

Foliage-feeding wild caterpillars have been collected and reared year-round by 1–30 rural resident parataxonomists in the Area de Conservación Guanacaste (ACG) in northwestern Costa Rica since 1978. The aim of the work was to describe the diversity and interactions of Lepidoptera and their associations with larval food plants and parasitoids in a diverse tropical community. A total of 457,816 caterpillars developed into a moth or butterfly, and these were identified to the family and species/morphospecies, with 151,316 having been successfully barcoded and assigned a Barcode Index Number (BIN) and/or “scientific name”. The host food plant was usually identified to the species or morphospecies. In addition to adult moths and butterflies, rearings also yielded many hundreds of species of parasitic wasps and tachinid flies, many of which were also DNA-barcoded and assigned a name and/or BIN. Increasingly over recent years, these have been identified or described by expert taxonomists. Here, we provide a summary of the number of species of ichneumonoid (Ichneumonidae and Braconidae) parasitoids of the caterpillars, their hosts, the host food plants involved, the bi- and tritrophic interactions, and their relationships to the caterpillar sampling effort. The dataset includes 16,133 and 9453 independent rearings of Braconidae and Ichneumonidae, respectively, collectively representing 31 subfamilies, all with parasitoid barcodes and host and host food plant species-level identifications. Host caterpillars collectively represented 2456 species, which, in turn, were collectively eating 1352 species of food plants. Species accumulation curves over time for parasitoids, hosts, and plants show various asymptotic trends. However, no asymptotic trends were detected for numbers of unique parasitoid–host and host–plant bitrophic interactions, nor for tritrophic interactions, after 1983, because climate change then began to conspicuously reduce caterpillar densities. Parasitoid host ranges, the proportions of specialists at the host species and host genus levels, host family utilisation, and host guild sizes show some differences among taxa and are discussed in turn. Ichneumonidae are shown to preferentially parasitise caterpillars of larger-bodied hosts compared to Braconidae. Several of the host plant species from which caterpillars were collected have been introduced from outside of the Americas and their utilisation by endemic parasitoids is described. The obligately hyperparasitoid ichneumonid subfamily Mesochorinae is dealt with separately and its strong association with microgastrine braconid primary parasitoids is illustrated. We discuss the implications for studies of tropical insect community food web ecology and make suggestions for future work. The aim was to make available the data from this remarkable study and to provide an overview of what we think are some of the more interesting relationships that emerge—other scientists/readers are expected to have different questions that they will go on to explore the data to answer. Full article

The cactus moth, Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae) is native to South America and has been used as a biocontrol agent of Opuntia (Cactaceae) in Australia and South Africa. Its invasion in North America has raised concerns for the native Opuntia in the USA and Mexico. We investigated the reproductive biology and rearing procedures of a host-specific potential biocontrol agent, Apanteles opuntiarum Martínez and Berta (Hymenoptera: Braconidae). Given the gregarious nature of the parasitoid larvae, we studied the morphology of the immature stages and evaluated evidence of polyembryony and superparasitism. We also investigated the effects of host exposure arena and host density on parasitism rates and wasp production. The morphological descriptions provide a basis for comparison with other species. Early larval instars of A. opuntiarum are similar to other microgastrine immature stages. However, the mature larva exhibits placoid sensilla in the epistomal region, a unique character not previously reported. We provide evidence that A. opuntiarum eggs are not polyembryonic; females frequently superparasitize and have an oviposition preference for larvae parasitized 1–2 d previously. Exposing larvae of C. cactorum to wasps while inside the cactus resulted in lower parasitism and fewer offspring from each host than exposing larvae in the arena without the cactus. Parasitism and mortality rates were higher at lower host densities, possibly due to reduced host group defensive behavior. These results suggest that preference for superparasitism, host defensive behavior, and interactions with the cactus may play an important role in per-host wasp production under laboratory conditions. Full article