Host Hemolymph Research Articles

Immunocytochemical localization of host (Apis mellifera) proteins in growing oocytes of a hemophagous mite (Varroa jacobsoni) by the unlabeled antibody—enzyme (PAP) method

The mite, Varroa jacobsoni is a hemophagous ectoparasite of honeybees (Apis spec.). Host hemolymph proteins are resorbed by Varroa without digestive degradation. By immunocytochemical methods, these foreign proteins can be localized in growing Varroa oocytes; they are assimilated into the eggs.

An investigation of possible Romanomermis culicivorax proteins in the hemolymph of Culex pipiens

The role of Romanomermis culicivorax in the degradation of hemolymph proteins in infected fourth-instar Culex pipiens was evaluated. Electrophoresis of proteins from hemolymph of C. pipiens, infected and control, revealed no new proteins in the hemolymph of infected mosquito larvae. Protein patterns from homogenates of R. culicivorax were compared with those from infected hemolymph and no proteins of parasite origin could be detected in the host hemolymph. Rabbit antibodies to R. culicivorax did not react with hemolymph of infected C. pipiens, a further indication that parasite proteins were absent from the host hemolymph. Proteases were located on polyacrylamide gels by their ability to digest gelatin. Appreciable proteolytic activity was found in the hemolymph of control mosquitoes, whereas activity in the hemolymph of infected mosquitoes and homogenates of R. culicivorax was nearly undetectable. Quantitative estimates of protease activity were made with two substrates, dimethylcasein and hemoglobin. Protease activity in hemolymph from C. pipiens larvae, control and infected, were not significantly different. However, the activity estimated for homogenates of R. culicivorax was 100 times less than that for hemolymph of C. pipiens larvae.

Sterols in the Trophosomes of the Mermithid Nematodes Neomesomermis flumenalis and Romanomermis culicivorax Relative to Sterols in the Host Hemolymph

The sterols in the trophosomes of the mermithid nematodes Romanomermis culicivorax and Neomesomermis flumenalis were identified tentatively and compared with the sterols in the hemolymph of their larval insect hosts, Aedes aegypti and Simulium venustum, respectively. The C26 sterol 22-trans24-norcholesta-5, 22-dien-33,-ol was predominant in the free sterol and sterol ester fractions of both nematodes. 22-dehydrocholesterol was a major component of esterified and nonesterified sterols in the trophosomes of R. culicivorax and of free sterols in the trophosomes of N. flumenalis. Cholesterol was not a major trophosomal component in either of the nematodes. The host hemolymph contained cholesterol and 38-sitosterol as the principal free sterols in A. aegypti and as the only detectable free sterols in S. venustum. The evidence suggests that the mermithids have some capacity to interconvert sterols supplied by the hosts. Mermithid nematodes parasitize the hemocoel of insects during a portion of the larval development of the insects. Nutrients available in the host's hemolymph are transported across the cuticle of the nematode (Rutherford et al., 1977), then stored in a structure known as a trophosome for subsequent utilization by nonfeeding, free-living stages. Lipids, apparently in the form of a lipid-protein complex, constitute the predominant storage product of Agamermis decaudata (Chitwood and Jacobs, 1938) and Mermis nigrescens (Denner, 1968), mermithid parasites of grasshoppers. In Romanomermis culicivorax and Neomesomermis flumenalis, mermithid parasites of larval mosquitoes and blackflies, respectively, trophosomes contain substantial amounts of lipids (Ittycheriah et al., 1977; Gordon et al., 1979); in decreasing order of prevalence, these are in the form of triacylglycerols, phospholipids, sterol esters, and free sterols (Gordon et al., 1979). The fatty acid composition of the triacylglycerol and sterol ester fractions was investigated and related to metabolites available in the host hemolymph (Gordon et al., 1979), but no information was presented concerning the sterol components of the trophosomes and their derivation from the host hemolymph. Nematodes thus far investigated require sterols as essential dietary components (DutReceived for publication 31 July 1979. ky et al., 1967b; Hieb and Rothstein, 1968; Cole and Dutky, 1969; Lu et al., 1977). Thus, as part of our continuing investigation for nutritional information pertinent to the in vitro culture of R. culicivorax and N. flumenalis, we examined the sterol composition of their trophosomes and precursors available in the host hemolymph. Nematodes studied thus far are unable to biosynthesize sterols de novo (Rothstein, 1968; Cole and Krusberg, 1968; Barrett et al., 1970; Willett and Downey, 1974). Thus, it is probable that the mermithids rely upon sterols in the host hemolymph for dietary sterol requirements. Although the sterol composition of whole insects has been investigated extensively (Thompson et al., 1972; Svoboda et al., 1975), there is a dearth of information concerning hemolymph sterols-no studies have been done on the sterol c mposition of culicid or simuliid hemolymph. Accordingly, the hemolymph sterol composition of larval Simulium venustum, a host in Newfoundland for N. flumenalis, and of larval Aedes aegypti, laboratory host for R. culicivorax, was examined to provide basic information on the availability of sterols to the

The effect of parasitism by Aphidius smithi (Hymenoptera: Aphidiidae) on the food budget of the pea aphid, Acyrthosiphon pisum (Homoptera: Aphididae)

Parasitism by Aphidius smithi affected the food budget of its host, Acyrthosiphon pisum, fed on a synthetic diet. During the embryonic stage of the parasite, the weight-specific rates of feeding, food assimilation, and growth were less in parasitized aphids than in controls. In the presence of a developing parasite larva, aphids ingested more food but assimilated it less efficiently; they achieved the same or a higher relative growth rate than nonparasitized aphids as a result of having either a higher feeding rate or a higher efficiency of incorporation of assimilated food, or both. Honeydew excretion was up to 129% higher in aphids containing a parasite larva. Parasitism by A. smithi did not obviate host feeding and capacity for growth until host size was sufficient for the successful development of the parasite larva.It is suggested that the nutritional requirements of the parasite larva differ from those of the aphid. Thus parasitism affects the homeostatic regulation of aphid feeding and food assimilation by causing an imbalance of nutrients in the host's haemolymph.

Lipids in the storage organs of three mermithid nematodes and in the hemolymph of their hosts

1. 1. Trophosomes of the mosquito parasitic mermithid Romanomermis culicivorax and two strains of the blackfly parasitic mermithid Neomesomermis flumenalis contained in order of prevalence: triacylglycerols, phospholipids, sterols and sterol esters. 2. 2. Triacylglycerols in the trophosomes comprised a wide array of fatty acids, sterol esters a smaller variety. 3. 3. The degree of unsaturation of triacylglycerols and sterol esters was greater for N. flumenalis than R. culicivorax. 4. 4. The hemolymph of the three host species ( Aedes aegypti, Prosimulium mixtum/fuscum, Simlium venustum) contained an assortment of fatty acids, with a higher degree of unsaturation in the simuliids than in the culicid. 5. 5. The overall lipid concentration of the blood of A. aegypti was unaltered by parasitism, but the mermithid caused an increase in the myristic acid:palmitic acid ratio in the free fatty acid fraction of the host's haemolymph.

Ultrastructure of the polygerm ofAgeniaspis fuscicollis Dalm. (Chalcidoidea, Hymenoptera)

The extraembryonic food supply of developingAgeniaspis fuscicollis polygerm from the host haemolymph is mediated by the trophamnion. The nutritive materials are absorbed by micropinocytosis. Besides microvilli and micropinocytotic vesicles, the following organelles appear in the trophamnion: multivesicular bodies, dictyosomes, mitochondria, and microtubules. The multivesicular bodies may be considered as a form of yolk. The storage material of the trophamnion is lipid. Numerous polyribosomes appear in the inner part of the trophamnion indicating intense protein synthesis. Food supply from the trophamnion to the embryo cells also proceeds by micropinocytosis. The polyembryo is surrounded by a cyst made up of host cells. Large numbers of tracheoles supplying the developing parasitic embryos with oxygen are invaginated into the cyst cells. The ultrastructure of theAgeniaspis fuscicollis polygerm shows a close trophic relationship between the polyembryonally developing parasite and its host.

AN ARTIFICIAL HOST: ENCAPSULATED SYNTHETIC MEDIUM FOR IN VITRO OVIPOSITION AND REARING THE ENDOPARASITOID ITOPLECTIS CONQUISITOR (HYMENOPTERA: ICHNEUMONIDAE)

This note reports the first in vitro oviposition and rearing of a parasitic insect, the endoparasitoid wasp Itoplectis conquisitor (Say), a male, on an artificial host consisting of an encapsulated synthetic, or meridic (Dougherty 1959, p. 53), medium.Parasitic insects, of course, have been reared in vitro on meridic diets (House 1954; Yazgan 1972; Thompson 1975). Some were reported to oviposit into artificial objects (Arthur et al. 1972; Rajendram and Hagen 1974; Hoffman et al. 1975). Trichogramma pretiosum Riley laid viable eggs and development to adults occurred in small wax-resin spheres filled with host haemolymph (Hoffman et al. 1975).

Phenoloxidase activity in the haemolymph of parasitized and unparasitized Heliothis virescens

Hymenopterous parasitoids of Heliothis virescens are able to evade the immune mechanisms of their host, especially the ability of the host to encapsulate foreign objects within a haemocyte capsule. This encapsulation is often accompanied by melanization. Our present findings show that hosts parasitized by Microplitis croceipes, Cardiochiles nigriceps and Campoletis sonorensis show changes both in the amount of melanin formed when their haemolymph is exposed to air and in the total protein as determined by the Folin phenol reagent. Furthermore, these changes are promoted by each of the three parasitoids in a different way. However, none of these parasitoids was able to alter the levels of host phenoloxidase as measured by the ability of the haemolymph to convert 4-methylcatechol to its quinone. The hymenopteran egg must therefore escape encapsulation in Heliothis in a way other than through inhibition of phenoloxidase, since the melanization reactions in the host's haemolymph are apparently unimpaired, particularly during the egg stage, by either the egg or venom of any one of the three parasitoids.

Food conversion efficiency of a parasitic wasp, Nemeritis canescens

Abstract. 1. The calorific efficiency with which N. canescens converts the larva of E. kuehniella into its own tissues has been measured by microbomb calorimetry.2. The calorific values found for Ephestia larvae are high in comparison with those of other insects and may be associated with their high fat content.3. The growth efficiency of 61% achieved by Nemeritis is sustained by the higher assimilation efficiency of 94%, owing to the parasitoid's habit of feeding directly on the host's haemolymph.4. The overall efficiency of conversion of adult moth (host) to adult ichneumonid (parasitoid) is of the order of 59% which is broadly representative of endoparasitoids and higher than that achieved by true predators.

Effects of the mermithid nematode Mermis nigrescens on the levels of hemolymph and fecal uric acid in its host, the migratory locust Locusta migratoria

Second- and third-instar nymphs of the migratory locust Locusta migratoria were infected with ova of the mermithid nematode Mermis nigrescens then compared with a group of uninfected (control) insects with respect to hemolymph and fecal uric acid levels. Twenty-four days after infection (i.e. when parasitic development had been completed), the hemolymph of infected hosts contained over five times the concentration of uric acid as that of controls, while the concentration of fecal uric acid was reduced to one-quarter of the control level in parasitized insects. These alterations of blood and fecal uric acid levels owing to mermithid parasitism are discussed with respect to the physiology of the host–parasite relationship.

Effect of calyx fluid from an insect parasitoid on host hemolymph dry weight and trehalose content

Effect of calyx fluid from an insect parasitoid on host hemolymph dry weight and trehalose content

Probopyrus pandalicola: Discontinuous ingestion of shrimp hemolymph

Grass shrimp, Palaemonetes pugío, were injected with 14C-labelled amino acids to determine hemolymph losses caused by an ectoparasite, the isopod Probopyrus pandalícola (Packard) (Epicaridea; Bopyridae). The female parasites were removed from labelled shrimp at intervals over 36 hr to monitor hemolymph ingestion. The parasites were found to feed discontinuously throughout the host's molt cycle, ingesting an average of 7–9 μl of hemolymph over a 24-hr period. Feeding was curtailed in darkness; probopyrids consumed only 2–3 μl of hemolymph after 12 hr in the dark. In all experiments, a number of parasites did not feed. The results of this study indicate that significant losses of the host's hemolymph result from the feeding activity of P. pandalicola. The determination of these losses is essential to begin testing the hypotheses that losses of hemolymph inhibit gonadogenesis in the host by either (i) creating a nutrient imbalance or (ii) depleting titers of reproductive hormones.

Endosymbionts of Sitodrepa panicea

Morphological and physiological characteristics of seven strains of yeast-like symbionts isolated from Sitodrepa panicea justify their inclusion into the genus Torulopsis as a new species: T. buchnerii. The symbiotic relationship is mutually beneficial: the symbionts obtain some nitrogenous compounds and carbohydrates, such as proline and trehalose from the host's hemolymph, and synthesize and make available to the host all the essential amino acids and vitamins, except biotin.

Neoaplectana carpocapsae: Encapsulation in Aedes aegypti and changes in host hemocytes and hemolymph proteins

Following encapsulation of a nematode parasite Neoaplectana carpocapsae by larval Aedes aegypti, there were significant decreases in both the total hemocyte count and in the number of DOPA-oxidase positive hemocytes within the anal papillae. Ligation experiments indicate these hemocytes are not necessary for successful capsule formation. The possibility of these changes resulting from a pathological condition created by the parasite are discussed. Disc electrophoresis revealed several changes in the protein migration pattern of A. aegypti hemolymph following encapsulation of N. carpocapsae. Gels stained with amido schwartz showed a shift in certain bands, a reduction in intensity of another, and the presence of an additional protein fraction. These changes appear to be specific for parasitism and/or encapsulation. Incubation of gels in DOPA solution revealed an increased intensity of one protein fraction which is not specific for encapsulation but may be the result of a wound response. It appears that some protein is released by the host or by the parasite in response to parasitism. While the function of this protein is unknown, it may play a role in the defense reactions of the host.

Trehalose and glucose levels in the hemolymph of Heliothis virescens parasitized by Microplitis croceipes or Cardiochiles nigriceps

1. 1. Heliothis virescens larvae were parasitized by either Microplitis croceipes or Cardiochiles nigriceps. 2. 2. Hemolymph trehalose levels from host larvae parasitized by M. croceipes nearly tripled within 1 day following parasitization and remained elevated during parasitoid development. 3. 3. C. nigriceps did not affect trehalose levels. 4. 4. Neither parasitoid affected the level of glucose in the hemolymph of its host. 5. 5. M. crociepes prevented any significant increase in host hemolymph dry weight beyond day 0 values; whereas, C. nigriceps elevated the dry weight during the latter part of its development.

The Development of the Immature Stages of Chelonus inanitus123

In Israel, Spodoptera littoralis (Boisduval) is attacked by the parasitoid, Chelonus inanitus (L.), the development of which was studied. C. inanitus has 3 larval instars which were measured and described. In fresh host eggs the parasitoid female lays her eggs in the host egg under the outer shell (chorion) of the egg but outside the host egg cell. Later the 1st instar parasitoid penetrates to the yolk and enters the haemolymph of the embryo before the host hatches. The 3 instars of C. inanitus float on the host haemolymph between the Malpighian tubules. Average times required for development of C. inanitus eggs, larvae, and pupae were determined. Synchronization between the development time of the parasitoid and its hosts was found at various temperatures. Parasitoid-host relationships were examined and are discussed.

Parasitoid egg shell changes in a suitable and unsuitable host

The egg shell of the braconid, Cardiochiles nigriceps , Viereck consists of two distinct layers: an inner, crystalline, proteinaceous chorion, and microvilluslike projections embedded in an outer fibrous chorion. In a suitable host the fibrous layer and projections are slowly lost during the first 12 hours. A new granular layer appears by 24 hours in place of the projections and fibrous layer. The structure of the fibrous outer layer of the egg shell is lost 2 hours after oviposition in an unsuitable host. The outer fibrous layer either changes to, or is replaced by, a microflocculate or coagulum by 6 hours. The projections persist through the first 12 hours but show signs of degeneration prior to encapsulation. The microflocculate increases in density until encapsulation by the hemocytes in about 24 hours. Hemocytes nearest the egg shell appear to show points of attachment. The possible role of the parasitoid egg and the host hemolymph is discussed with respect to immunity.

Effects of the parasitization of a braconid, Apanteles, on the blood of its host, Pieris

Parasitization of a braconid wasp, Apanteles glomeratus, of larvae of a common cabbage butterfly, Pieris rapae crucivora, caused changes in differential haemocyte count (DHC), total haemocyte count (THC), and encapsulative capacity against dead eggs of Apanteles in the fourth and fifth instar host larvae. However, no correlation could be found between the number of Apanteles eggs deposited and THC of the middle fourth instar host larvae or between the number of parasitoid larvae and specific gravity of the haemolymph from the late fifth instar host larvae. From the changes in DHC and in THC of both non-parasitized and parasitized Pieris larvae, an increase in the number of plasmatocytes of non-parasitized Pieris larvae in the early fourth instar period was supposed to be due to transformation of prohaemocytes into plasmatocytes, and a low population of plasmatocytes of parasitized larvae in the comparable period was assumed to be due to a suppression of transformation of prohaemocytes by some factor released from the parasitoid eggs. Failure of the parasitized fourth instar Pieris larvae to encapsulate injected dead eggs of Apanteles indicated that the parasitoid embryos were, in some way, actively inhibiting the encapsulation reactions of the host. The increase in THC of the parasitized fifth instar larvae could not be ascribed to a decrease in the volume of host haemolymph. Rather it could be interpreted by a suppression of adhesive capacity of haemocytes in the host haemocoel to tissue surfaces. Reduced encapsulative capacity of the parasitized fifth instar larvae might be attributed either to a depression of the adhesive activity of plasmatocytes resulting from a depletion of energy source for haemocytes in the host haemolymph by parasitization, or from an active suppression of adhesiveness of the plasmatocytes by secretions from ‘giant cells’ (teratocytes) originated from the parasitoid.

Teratocytes: Growth and numbers in the hemocoel of Heliothis virescens attacked by Microplitis croceipes

When the egg of Microplitis croceipes hatches in its host, Heliothis virescens, spherical cells (teratocytes) from the extraembryonic membrane are released into the host's hemolymph. Approximately 750 teratocytes are liberated from the parasitoid egg, and they average 10.5 μm in diameter when released. These cells increase in size, reaching a maximum average diameter of 140 μm in 8–9 days. The developing parasitoid emerges from the host in 9 days. The host remains alive and contains approximately 750 teratocytes, indicating that the teratocytes are not consumed by the parasitoid. These results suggest that teratocytes are not a direct source of nutrition for the developing parasitoid. Observations showed that encapsulation can occur in the presence of teratocytes even following the emergence of the parasitoid. The results indicate that teratocytes do not block the host's ability to encapsulate certain foreign materials within its hemocoel.

Mermithid parasitism, protein turnover and vitellogenesis in the desert locust, Schistocerca gregaria forskål

1. 1. Using polyacrylamide disc electrophoresis, eight soluble protein fractions were demonstrable in measurable amounts within the yolk of Schistocerca gregaria. 2. 2. Female locusts were infected 3 days after their imaginal moult with equal doses of Mermis nigrescens ova and electropherograms of their haemolymph and fat body proteins were compared with a group of uninfected (control) females. Effects of the parasite upon host protein turnover were appraised in relation to the host's gonotropic cycle. 3. 3. The nematode caused only a sporadic depletion of vitellogenic and non-vitellogenic protein fractions before and during the vitellogenesis period of controls (initial 2 weeks' infection). The ability of the terminal oocytes to sequester vitellogenic proteins from the host haemolymph was impaired by the parasite, so vitellogenesis commenced but was not completed in infected hosts. 4. 4. At 3 weeks' infection, haemolymph protein fractions were significantly diminished (cf. controls) by parassitism but were not so depleted 3 days later. Concurrently, terminal and penultimate oocytes of infected locusts were resorbed. 5. 5. Effects of the nematode on the insect's fat body soluble proteins preceded analogous changes in haemolymph protein fractions. Two weeks after infection, ten of seventeen soluble protein fractions were significantly depleted in the fat bodies of infected locusts (cf. controls). Three weeks after infection, only six fat body protein bands were significantly depleted in infected insects (cf. controls) whilst four such protein fractions were present at significantly higher levels than in the controls. 6. 6. The nematode stimulates catabolism and/or suppresses anabolism of proteins by the host fat body, to provide a dietary source of amino acids within the haemolymph. This effect of M. nigrescens parasitism upon protein turnover in the locust is discussed in relation to host vitellogenesis, growth requirements of the developing parasite and possible involvement of the host endocrine system.