Diet is one of the most common influences on parasitoid reproductive traits. The life span, mating ability, fecundity, fertility and sex ratio of parasitoids can be affected by the quality of the adult diet. In the field, parasitoids can rely on different hosts and non-host nutrient sources, such as floral and extrafloral nectar, hemipteran honeydew and pollen, and various artificial diets have been used in mass rearing. In addition, some parasitoid species obtain nutrients by feeding on their host while adult (host feeding). In this review, we summarize current knowledge on the impact of the adult diet on the reproductive behavior of hymenopteran and dipteran parasitoids, with a particular focus on longevity, offspring production and host searching traits. First, we focus on food preferences and learning abilities of parasitoids to discriminate high-quality diets. Second, we analyze the impact of the adult diet on longevity, examining different natural and artificial food sources as well as the effect of their concentration and frequency. Third, we highlight the impact of the adult diet on host foraging. Fourth, we review the impact of adult diet on parasitoid offspring with special reference to (1) egg load, maturation and resorption, (2) parasitism and (3) progeny production and sex ratio. Finally, a number of implications for biological control and integrated pest management are discussed.

The impact of adult diet on parasitoid reproductive performance

Most organisms must ingest water to compensate for dehydration. In parasitic wasps, the importance of water and the behaviors driving its consumption are poorly understood. Here, we describe a water-intake strategy of Pachycrepoideus vindemmiae, a parasitoid of spotted-wing drosophila (SWD, Drosophila suzukii). Longevity measurements indicated that P. vindemmiae benefits from drinking water and from host-feeding on the water-rich hemolymph of SWD pupae. After exposing wasps to different water regimens, we observed increased host-feeding in water-deprived wasps despite honey availability. This resulted in greater SWD mortality because the host-feeding process killed the pupae, and because wasps that engaged in greater host-feeding parasitized more hosts. Behavioral observations showed that the host-feeding time of water-deprived wasps doubled compared to water-fed individuals. Host-feeding did not affect parasitoid offspring mortality. We conclude that P. vindemmiae benefits from ingesting water and that it host-feeds on SWD pupae as a water-intake strategy. These are interesting findings not only because water has rarely been reported as a critical nutrient for adult parasitoids, but especially because preying for the purpose of hydration is not a common strategy in nature. This strategy enhances parasitoid survival and reproduction, with positive consequences for its host-killing capacity and potential as a biocontrol agent.

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Water-Deprived Parasitic Wasps (Pachycrepoideus vindemmiae) Kill More Pupae of a Pest (Drosophila suzukii) as a Water-Intake Strategy.

Pachycrepoideus vindemmiae is a wasp that parasitizes and host-feeds on pupae of the invasive spotted-wing drosophila (SWD, Drosophila suzukii). Few studies have addressed interactions between these two species and little is known about the potential of this parasitoid as a biocontrol agent of SWD and the different variables that may affect it. Here, we investigated the impact of extrinsic and intrinsic factors on life-history traits of P. vindemmiae. Both constant (entire adulthood) and limited (30 minutes) supplies of water + honey, honey, or host increased parasitoid survival compared to controls (water or fasting). Water + honey caused the highest parasitoid survivals (35-60 days), independent of supply period, sex, and host availability. Females were intrinsically more resistant to water- and honey-deprivation than males, and host-feeding elevated such resistance even higher. Constant honey supply (either with or without water) supported the highest host-killing capacities (= capacity to kill hosts) (ca. 600 SWD pupae/wasp). However, in young females (4-9 days old), the impact of honey availability (with or without water) was insignificant while water deprivation (either with or without honey) caused the highest host-killing potential. This indicates that although sugar becomes a critical nutritional resource as females age, young females depend more on water than sugar to reproduce. Neither water nor honey affected the sex ratio of young females, but when we considered the entire adulthood, the availability of honey caused the lowest proportion of females (0.50), independent of water availability. Neither water nor honey affected parasitoid emergence rate (0.97), independent of female age. Based on survival and host-killing capacity, we conclude that P. vindemmiae has a tremendous biocontrol potential against SWD. Both limited and constant supply of water, sugar, and host increase parasitoid survival, while constant supply of water and/or honey enhance its host-killing potential and decrease sex ratio depending on maternal age.

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Factors affecting the biology of Pachycrepoideus vindemmiae (Hymenoptera: Pteromalidae), a parasitoid of spotted-wing drosophila (Drosophila suzukii).

Background: The destructive insect pest Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae) is a polyphagous species targeting many economically important plants. The extensive and arbitrary use of insecticides has resulted in the build-up of insecticide resistance and pesticide residues accumulating in food. Therefore, it is becoming evident that alternative pest management tools are needed to reduce risks to humans, the environment, and non-target organisms, and at the same time, they should be used in field application at the lowest cost. Methods: In view of this objective, the present study demonstrates the toxicity of lemongrass (Cymbopogon citratus (DC.) Stapf) essential oil (EO), against the black cutworm A. ipsilon under controlled laboratory conditions in terms of measuring the activity of peroxidase and detoxification enzymes. The chemical components of the EO were analyzed using GC–MS. Results: The results show that after 96 h post treatment, the LC15 and LC50 values were 427.67 and 2623.06 mg/L, respectively, of C. citratus EO on second-instar larvae of A. ipsilon. A slight significance in elongation of the larval duration with LC15 and LC50 value was found with control. By GC–MS analysis, the main compounds identified in the EO were α-citral and β-citral with percentages of 35.91%, and 35%, respectively. The oxidative stress indicates a significant increase in CAT and lipid peroxidase enzyme activity after 96 h post treatment at the LC15 and LC50. Conversely, the detoxification enzyme activity shows an inhibition of CarE and GST enzymes of larvae exposed to LC15 and LC50 values in response to C. citratus EO. Conclusions: The present data show that lemongrass EO has insecticidal activity against the black cutworm, A. ipsilon.

Insecticidal Activity of Lemongrass Essential Oil as an Eco-Friendly Agent against the Black Cutworm Agrotis ipsilon (Lepidoptera: Noctuidae)

Improvements in the industrial process involved in starch degradation have led to the search for thermostable, salt-loving amylolytic enzymes especially glucoamylase, an enzyme that can completely hydrolyze starch to glucose. In this research, glucoamylase was optimally produced in liquid culture from Aspergillus fumigatus and purified to homogeneity by ammonium sulphate precipitation, ion-exchange chromatography and gel filtration, giving a yield of 8.19% with 20-fold purification. The 50 kDa glucoamylase, molecular weight estimated by Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE) was highly stable over a wide pH range in the acidic region and also thermostable; retaining about 70% of initial activity after 60 min of incubation at 60oC. The purified enzyme was active on amylose, dextran and different starches with Km and Vmax values of 1.59 mg/mL and 14.33 U/mg respectively, when raw cassava starch was used as substrate. Remarkably, this glucoamylase possesses high salt-tolerant property, with about 50% residual activity after 24 h incubation in 3.0 M NaCl solution. Some metal ions including K+, Ca2+ and Mg2+ were activators of the enzyme while Cu2+, Pb2+ and Hg2+ inhibited its activity. The unique biochemical characteristics of this glucoamylase qualify it for biotechnological use especially in food, pharmaceuticals and biofuel industries.

https://www.rroij.com/open-access/raw-starch-degrading-acidicthermostable-glucoamylase-from-aspergillus-fumigatus-cfu01-purification-and-characterization-for-biotec-.pdf

Raw Starch Degrading, Acidic-Thermostable Glucoamylase from Aspergillus fumigatus CFU-01: Purification and Characterization for Biotechnological Application

The hypothesis that non-host-feeding synovigenic parasitoids are more likely to rely entirely upon teneral protein reserves for future egg and offspring production was tested in the present study. Protein-rich beebread was mixed with honey to form a paste (honey-beebread) and reproductive parameters of Cotesia vestalis were compared among females that were fed honey with or without beebread. Oviposition period lasted 3 and 8 days in unfed (but water-provided) and fed wasps, respectively. Satiated parasitoids attained peak offspring production within the first 2 days of eclosion, and production dropped sharply after 4 days. Wasps provided with honey-beebread produced more offspring and a more female-biased progeny than conspecifics that were raised on honey. In addition, posteclosion egg maturation progressed irrespective of diet and maximum egg load (102 mature eggs) was attained within 48 h of parasitoid emergence. Obtained results showed that supplementary protein sources could enhance some asp...

Effect of beebread on the reproductive performance of Cotesia vestalis

The braconid Cotesia plutellae (Kurdjumov) (Hymenoptera: Braconidae) is a major solitary, larval endoparasitoid of the diamondback moth, Plutella xylostella (L) (Lepidoptera: Plutellidae) The impact of dietary protein was investigated in the laboratory by comparing performance of C plutellae on honey, which is commonly used to rear the parasitoid, to that on a novel diet made of honey and protein-rich beebread Cotesia plutellae was highly stimulated by honey and honey-beebread, with a feeding response exceeding 95%, a level that is comparable with its responses to fructose, glucose, and sucrose The ability of honey-beebread to support host-parasitoid colonies was also comparable with that of honey However, parasitoids raised on honey-beebread suppressed diamondback moths in rearing cages 3 weeks before the honey-fed wasps The development time of C plutellae reared on honey with or without beebread showed no significant difference, but adult wasps lived longer on honey-beebread Mean developmental periods from oviposition to pupation and from pupation to adult emergence were 8 and 6 days, respectively Adult wasps raised on honey-beebread outlived their conspecifics that were raised on honey by at least 4 days Honey-beebread showed potential as a good food for rearing C plutellae in the laboratory, and its benefit in parasitoid production is discussed

https://bioone.org/journals/Journal-of-Insect-Science/volume-13/issue-86/031.013.8601/Suitability-of-a-Novel-Diet-for-a-Parasitic-Wasp-Cotesia/10.1673/031.013.8601.pdf

Suitability of a Novel Diet for a Parasitic Wasp, Cotesia plutellae

http://ppmj.net/index.php/ppmj/article/download/189/289

Insecticidal effect of lemongrass oil on behavioural responses and biochemical changes in cowpea weevil, Callosobruchus maculatus (Fabricius)

Insecticidal activities of hexane extracts of leaves and roots of siam weed and vetiver, and roots of neem were assessed against house fly, Musca domestica L. Mortality test was conducted using serial concentrations 20%, 10%, 5% and 2.5% of extracted oils while behavioural orientation of house fly to oil odour, antioviposition effect of oil toward the insects, biochemical reactions in treated flies and fitness of offspring were determined using 20% oil concentration. House fly mortality varied significantly with plant species and part of plant extracted (P < 0.001), concentration applied (P < 0.001) and time post-exposure (P < 0.001). All tested plant extracts showed potential as good control agents with average mortality ranging from 59-74%. However, significantly lower median lethal values (LC50 and LT50) separated vetiver as the most toxic plant against the insect pest. The plant oils repelled house flies (93-100%), reduced the number of larvae that hatched from laid eggs, lowered adult emergence and caused a significant reduction in size and weight of offspring. On the contrary, exposure to plant oils did not alter offspring sex ratio. In comparison to untreated house flies, plant oils induced biochemical stress in poisoned cohorts as evidenced in significant deviation of digestive enzyme (α- and β- amylases, lipase) activity and concentrations of detoxifying enzyme (glutathione-Stransferase), neurochemical enzyme (acetylcholinesterase) and energy metabolism biomolecules (total protein). Implications of obtained results for non-chemical control strategies are discussed.

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O J Soyelu

Papers

Effect of beebread on the reproductive performance of Cotesia vestalis

Suitability of a Novel Diet for a Parasitic Wasp, Cotesia plutellae

Insecticidal effect of lemongrass oil on behavioural responses and biochemical changes in cowpea weevil, Callosobruchus maculatus (Fabricius)

Effect of Neem, Siam Weed and Vetiver Oils on Physiological Reactions and Fitness of House Fly, Musca domestica L

Properties of Amyloglucosidase in the Digestive Tract of Periplaneta americana L. (Blattodea: Blattidae).