Jacob S. Ishay

The pheromone of the queen of the Oriental hornet, Vespa orientalis

Abstract From an extract of heads of the queens of the Oriental hornet, Vespa orientalis, a pheromone has been isolated and identified as δ-n-hexadecalactone:

Pharmacological activity of oriental hornet (Vespa orientalis) venom.

Abstract The pharmacological activity of Oriental hornet ( Vespa orientalis ) venom has been studied and some of its active substances characterized. The ld 50 (i.v.) of venom for albino mice was 2·5 mg per kg. The venom caused contraction of isolated smooth muscle preparations, bronchoconstriction in anesthetized guinea pigs and when injected intradermally into rats and rabbits increased the permeability of microcirculation vessels. After intra-arterial injection, the venom blocked the directly and indirectly induced single twitches of cat gastrocnemius-soleus and tibialis anterior muscles, but it did not affect nerve conduction. The venom possessed protease and hyaluronidase activities, released histamine from mast cells, caused hemolysis and was immunogenic when injected into rabbits. The following substances were found in the venom: histamine, acetylcholine, 5-hydroxytryptamine, kinin(s), adrenaline, noradrenaline and dopamine. It was postulated that the catecholamines present might prolong the local action of the venom and be responsible for its ‘blanching’ effect observed upon i.d. application.

Food exchange between adults and larvae in Vespa orientalis F

Abstract Colonies of Vespa orientalis cannot exist without the larvae or, more specifically, without larval salivary secretion, which is the only source of raw materials for nitrogen metabolism and egg production available to the workers and the queen, who do not themselves possess the proteases necessary for protein degradation. This finding suggests that social life among wasps is probably a symbiosis between the adults and larvae.

Caste determination by social wasps: Cell size and building behaviour

Abstract Oviposition and cell-building activities were studied experimentally in two species of Vespinae, Vespa orientalis and Paravespula germanica . Queen-right and queenless colonies were allowed to oviposit into and raise brood within comb cells that were smaller than, equal to, or larger than normal. Transfer of eggs of 1st to 3rd instar larvae from worker cells to queen cells results in the development of queens, while the reverse transfer results in the production of workers. Evidence is presented to suggest that in Vespinae, the cell size determines the caste of the developing brood. The workers, possibly under the influence of queen pheromones, actively determine the various castes of the future generation by their treatment of the brood or of the cells which house it.

The presence of insulin in and some effects of exogenous insulin on hymenoptera tissues and body fluids

Abstract o 1. Radioimmunoassay technique has revealed the presence of insulin in the tissues of various Hymenopteran insects, including the honeybee Apis mellifera , the Oriental hornet Vespa orientalis and several other Paleoarctic social wasps, the Mason bee Chalicodoma sicula , the cuckoo wasp Chrysis sp. and the weaver ant Polyrachis simplex . 2. Laboratory determinations carried out in vivo and in vitro on several insects have shown that bovine insulin injected into insect hemolymph or incubated together with the hemolymph causes a significant drop in the glucose level of the fluid.

Comb bulding by the oriental hornet (Vespa orientalis)

Abstract Oriental hornet young queens and workers have been induced to build combs in observation boxes. Both workers and queens displayed bulding activity over a period of 2 to 6 weeks, which is approximately the time range necessary for the development of one generation (from egg to pupa or maximally from egg to imago). Building activity and the comb architecture have been found to be influenced by such factors as: size of group, age of hornets, amputation of wings, tarsi and tips of antennae and light, and by feeding with mannose and barbiturates. Cell size is influenced by various drugs.

Geotropic sensitivity exhibited by single hornets: the influence of caste, age, light and temperature

Hornet Vespa orientalis, Hymenoptera: Vespinae) workers, queens and males, aged 0-24 hours (i.e. juveniles) and 24 hours and more (i.e. adults) were tested for their responses to changes in the direction of the gravitational force while placed on a flat surface gradually tilted between 0.5 degree and 180 degrees. The tests were run on non-blind and blind hornets, at temperatures ranging between 18 degrees C and 35 degrees C, in daylight as well as in the dark. Up to 18 hours of age, negative phototaxis prevailed among the hornets, which displayed a clear preference for remaining in the dark regardless of the geotropic position. Between 18-24 hours of age, there was gradual appearance of a sensitivity to change in the geotropic position. Above 24 hr of age, the hornets became sensitive to changes in their declinations, with workers becoming sensitive at a 3-5 degrees declination, queens at 4-5 degrees and males at a declination of 8-l9 degrees from the horizontal. Hornet response takes the form of an upward climb, to the highest point of the test surface. Such response required a temperature exceeding 24.8-25 degrees C for workers, 23.2 degrees C for queens and 20.8-21 degrees C for males.

Photoelectric properties of the ‘yellow strips’ of social wasps

The yellow strips on the cuticle of social wasp workers become photoconductive following irradiation with light, the effect being perfectly reversible.

Phospholipases A and B activities of the oriental hornet (Vespa Orientalis) venom and venom apparatus

Phospholipases A and B activities of the oriental hornet (Vespa orientalis) venom and venom apparatus. Toxicon15, 141–156, 1977.—Oriental hornet venom is a rich source of both phospholipase A (PhA) and phospholipase B (PhB) activities. This was shown by incubating venom with egg yolk or with pure lecithin and lysolecithin. Activity was measured by titrating liberated fatty acids and by phosphorus analyses of separated phospholipids from thin-layer chromatographic plates. Both lecithin and lysolecithin were rapidly hydrolyzed by venom at pH 4 and 8. With egg yolk as substrate, the optimum Ph activity was observed at pH 5 although considerable activity was observed from pH 3·5 to 9·5. In contrast purified substrates showed greater activity at an alkaline pH, whether assay was in the presence of collidine-acetate or Tris buffer or in the presence or absence of ether. Ether dramatically changed the optimal pH for Ph activity, with egg yolk as substrate, from acidic to alkaline. It is not known whether these PhA and PhB activities are dual activities of a single enzyme or activities of two separate enzymes. The venom has neither PhC nor lipase activities. PhA and PhB activities were observed not only in pure venom (V), but also in venom sacs (VS) where the venom is stored, in the acid (venom) glands (H+) where the venom is produced, and in the alkaline (Dufours) gland (OH−) whose function is unknown. The release of free fatty acids from egg yolk at pH 5 was in the ratios of 1 (V): 0·13 (VS): 0·04 (H+): 0·30 (OH−). Measurements of Ph activities in combinations of the above preparations showed that strong activators or inhibitors of the enzyme are not present. The mid-gut, fat body and hemolymph of the hornet showed Ph activity only equal to about one-half of one per cent of that of the OH− gland. Antisera produced against V, VS, H+ and OH− were cross-reactive and inhibited to varying degrees the Ph activities of each of the above preparations. The highest titre antisera were produced in rabbits injected with V or VS, in contrast to the low titres produced with H+ and OH− glands. Low Ph activity is detectable in the venom sacs 2 days prior to emergence, with 20-fold higher activities being observed at 5 days of age. The oriental hornet may be extremely useful as a rich source of not only PhA but also PhB activities. The effects of this latter enzyme on biological systems have not been thoroughly evaluated. The drastic disruption of phospholipid structure and hydrophobic binding forces between phospholipid and protein, by the combined PhA plus PhB activities, may be responsible for some of the pharmacological actions of hornet venom.

Catecholamines in social wasps

Abstract 1. 1. Various tissues originating from several species of social wasps showed significant amounts of catecholamines (noradrenaline, adrenaline, dopamine and 5-hydroxytryptamine). 2. 2. Dopamine proved to be the most abundant among the catecholamines examined. 3. 3. The data are discussed in regard to possible functions of catecholamines in wasps.