Polistes versicolor (Hymenoptera: Vespidae), an Introduced Wasp in the Galapagos Islands: Its Life Cycle and Ecological Impact

The yellow paper wasp, Polistes versicolor (Olivier) was first recorded in the Galapagos archipelago in 1988. Its life cycle and ecological impacts were studied on two islands 11 yr after it was first discovered. This invasive wasp adapted quickly and was found in most environments. Colony counts and adult wasp monitoring showed a strong preference for drier habitats. Nest activities were seasonally synchronized, nest building followed the rains in the hot season (typically January–May), when insect prey increases, and peaked as temperature and rains started to decline. Next, the number of adult wasps peaked during the cool season when there is barely any rain in the drier zones. In Galapagos, almost half of the prey loads of P. versicolor were lepidopteran larvae, but wasps also carried spiders, beetles, and flies back to the colonies. An estimated average of 329 mg of fresh insect prey was consumed per day for an average colony of 120–150 wasp larvae. The wasps preyed upon native and introduced insects, but likely also affect insectivorous vertebrates as competitors for food. Wasps may also compete with native pollinators as they regularly visited flowers to collect nectar, and have been recorded visiting at least 93 plant species in Galapagos, including 66 endemic and native plants. Colonies were attacked by a predatory moth, Taygete sphecophila (Meyrick) (Lepidoptera: Autostichidae), but colony development was not arrested. High wasp numbers also affect the activities of residents and tourists. A management program for this invasive species in the archipelago is essential.

The effect of sublethal concentrations of malathion on some biological parameters of the ectoparasitoid wasp, Habrobracon hebetor (Say, 1836)

<em><em></em></em><p>The ectoparasitoid wasp, <em>Habrobracon hebetor</em> (Say, 1836) (Hym.: Braconidae) is one of the most important natural enemies of many pests in Iran. In this study, the effects of sublethal concentrations of malathion (LC₁₀ and LC₂₅) on biological parameters of the adult wasp including parasitism percentage, male production and longevity of the parasitoid in different growth stages (larvae, pupae and adult) were investigated. The experiments were conducted at 26 ± 1 °C, 60 ± 5 % RH, and 16L:8D h photoperiods. The effect of sublethal concentrations of malathion on adults was determined by exposure of wasp to insecticide, and in the case of larvae and pupae, immersion method was used. Based on the results, with the increase of toxic dose, the percentage of parasitism in adult decreased from 95.6 5% to 87.78 %, compared to the control treatment. Male production increased from 22.73 % in control to 56.38 % at LC₂₅ concentration. Also, the percentage of parasitism of the malathion-impregnated wasp larvae decreased from 87.78 to 22.92%, compared to the control treatment. Male production from 30.94 % in the control increased to 39.63 % at the LC₂₅ concentration. In addition, the percentage of parasitism in the wasp pupae impregnated with malathion was reduced from 93.33 to 88.89 %, respectively. Male production increased from 22.98 in the control to 37.23 % in the LC₂₅ concentration. The data showed that pupae were more susceptible to sublethal concentrations than the larvae.</p>

Isodontia Mexicana (Hymenoptera, Sphecidae), a New Invasive Wasp Species in the Fauna of Ukraine Reared from Trap-Nests in the Crimea

Isodontia mexicana (Hymenoptera, Sphecidae), a New Invasive Wasp Species in the Fauna of Ukraine Reared from Trap-Nests in the Crimea. Fateryga, A. V., Protsenko, Yu. V., Zhidkov, V. Yu. - Th e North American wasp Isodontia mexicana was found for the first time in Ukraine in trap-nests operated near Pushkino (southern coast of the Crimea) in 2012. Th ree nests contained five cocoons, from which only one adult wasp emerged in 2013, allowing the positive identification; other cocoons were either empty (one) or destroyed by Melittobia acasta (three). Such a find of a newly established invasive species in Ukraine represents the easternmost point in its European range and possibly the most remarkable jump-dispersal event in its distribution.

Oviposition by introducedOphelimus eucalypti(Hymenoptera: Eulophidae) and morphogenesis of female-induced galls onEucalyptus saligna(Myrtaceae) in New Zealand

An Australian gall-inducing eulophid,Ophelimus eucalypti(Gahan) was first recorded on the foliage ofEucalyptus botryoidesafter it invaded New Zealand in 1987. It has spread throughout the eucalypt plantations in the North Island and in the northern parts of the South Island affecting several species ofEucalyptusin the section Transversaria (subgenusSymphyomyrtus). Because gall-inducing insects usually have extremely narrow host ranges,O. eucalyptithat induces galls onE. salignaandE. botryoidesis currently recognized as a biotype,O. eucalypti(Transversaria). Heavily galled leaves abscise from the plant. Repeated defoliation led to widespread die-back of susceptible eucalypt species in the 1990s. Female larvae ofO. eucalyptiinduce circular, protruding galls on the leaves ofE. botryoidesandE. saligna, whereas the males induce pit galls on the same species. The biology ofO. eucalyptifemales and the development of their galls are described. Adult femaleO. eucalyptiantennate the leaf surface before inserting the ovipositor (otherwise concealed within the metasomal apex) into the young host leaf. The egg is inserted at approximately 45° and discharged between differentiating palisade cells. Callus-type cells surround the egg chamber, but cytologically specialized nutritive cells appear once the egg hatches and the larva begins to feed. The gall also differentiates a multi-layered sclerenchymatous tissue around the nutritive tissue. After feeding for many months, the larva pupates and the active nutritive tissue degenerates. The adult wasp emerges after cutting an exit hole through to the outside of the gall. Abscission of heavily galled leaves results in widespread defoliation and loss of growth and vigour in susceptible trees in New Zealand.

THE CHALCID SEED WASP, MEGASTIGMUS NIGROVARIEGATUS HYMENOPTERA: TORYMIDAE, ON ROSA RUGOSA THUNB. IN NOVA SCOTIA

Two naturalized populations and two planted populations of Rosa rugosa Thunb. were studied with respect to chalcid seed wasp infestation. Megastigmus nigrovariegatus Ashmead was found in hips from planted R. rugosa in Halifax and Dartmouth, Nova Scotia, but not from bushes at naturalized sites. The percentage of infested hips at the Halifax and Dartmouth locations was 26 and 31%, respectively. The percentage of infested achenes within a single hip varied widely from 3 to 79% at the Halifax site and 7 to 60% at the Dartmouth site.Adult emergence was over 75% successful when achenes were over 2 mm in diameter but less than 15% for smaller achenes. The exit hole on the achene faced the outer wall of the hip. Adults emerged later in Nova Scotia than in the United States and between 59 and 72% were female. More than one adult wasp was observed ovipositing on a single hip.

Effect of Parasitoid and Host Age on Oviposition and Emergence of Microplitis croceipes (Hymenoptera: Braconidae) an endoparasitoid of Helvicoverpa zea (Lepidoptera: Noctuidae)

The effect of parasitoid age and two instars of the host Helicoverpa zea (Boddie) were investigated for the endoparasitoid, Microplitis croceipes (Cresson). Third and fourth instars of H. zea were exposed to three different age ranges (3 to 5, 6 to 8, and 12 to 15-d-old) of mated adult female M. croceipes. No significant differences were shown in rate of parasitism regardless of parasitoid age or host instar. Significant differences (P &lt; 0.05) were found between parental age and adult wasp emergence, sex ratio, and number in pupal stage entering diapause. Six to 8-day-old parasitoids parasitizing third instar hosts yielded the highest percentage of adult emergence (47.5 ± 14%; X̄ ± SD), the highest percentage of females (79%), and the lowest percentage (4.5 ± 6%; X̄ ± SD) entering diapause during the test.

RATE OF DEVELOPMENT, REPRODUCTION, AND MASS-REARING OF APANTELES FUMIFERANAE VIER. (HYMENOPTERA: BRACONIDAE) UNDER CONTROLLED CONDITIONS

The temperature-dependent rate of development of the post-diapause larval and pupal stages of the spruce budworm parasitoid, Apanteles fumiferanae Vier., was estimated under controlled conditions. Parasitoid larvae required 289.0 degree-days (DD) above a threshold of 8.1 °C to complete development and the pupae required 106.2 DD above a threshold of 9.6 °C to complete development. Longevity of the adult wasp at several temperatures also was examined. Female wasps lived longer than male wasps at all temperatures. Wasps tended to mate more readily under natural than under artificial light conditions.Newly emerged female A. fumiferanae had few, if any, mature eggs in their ovaries. The number of mature eggs increased to a peak of 40–75 eggs, 4–12 days after eclosion of the adult. The pattern in number of ovipositions was similar to this pattern of egg availability. The daily rate of oviposition, however, was only about one-quarter the number of eggs available.These biological measurements are discussed in view of the development of a mass-rearing technique for this parasitoid.

A METHOD OF CAPTURING COLONIES OF AERIAL NESTING VESPID WASPS (HYMENOPTERA: VESPIDAE)

A method was developed for the transfer of intact medium-sized Dolichovespula arenaria colonies from their original locations, without damage to the nest and with minimal narcosis of the adult wasp population. The method necessitates a substantial manipulation early in the course of colony development, after which the nest is left to develop normally in situ until it is sufficiently populous to permit tranfer to a new location without intolerable loss of adult insects. We describe also a system for housing vespid colonies following relocation, together with a one-way tunnel system which has proved efficient for the purpose of collecting data on foraging activity.

Laboratory Biology of Phaenocarpa Persimilis Papp (Braconidae: Alysiinae), a Parasitoid of Drosophila.

P. persimilis is a recently discovered Australian parasitoid of several cosmopolitan and native species of Drosophila. It can be reared in the laboratory, and has a life cycle similar to that of other Hymenopterous insect endoparasites. An egg is laid in the host larva, and the adult wasp emerges from the host puparium. Various aspects of the wasp's behaviour and physiology, especially those features which may affect its relationship with its host in the field, were investigated in laboratory experiments. The results indicate that P. persimilis has many attributes which (potentially) allow it to be a very efficient parasitoid.