Behavioural Acceptability of Sitona lepidus (Coleoptera: Curculionidae) to the Parasitoid Microctonus aethiopoides (Hymenoptera: Braconidae) Using the Pathogenic Bacterium Serratia marcescens Bizio

Microctonous aethiopoides Loan has been introduced into New Zealand to control the lucerne pest Sitona discoideus Gyllenhal (Coleoptera: Curculionidae). Sitona lepidus Gyllenhal (Coleoptera: Curculionidae) a pest of clover ( Trifolium spp.), has recently established in New Zealand. Laboratory experiments to test the potential of M. aethiopoides to parasitize S. lepidus has resulted in very low levels of parasitism. To investigate whether there were behavioural or physiological barriers to successful parasitism, two experiments were conducted using the insect pathogenic bacterium. Serratia marcescens Bizio as a marker for parasitoid ovipositor penetration. Firstly, M. aethiopoides 'treated' with S. marcescens were exposed to weevils and rapid weevil mortality was used to indicate ovipositor penetration. Up to 50% mortality of S. lepidus occurred, which was comparable with mortality observed in the permissive host Listronotus bonariensis . Dissection of S. lepidus exposed to parasitoids treated with distilled water showed that ca. 21% contained parasitoid eggs of which 98% were nonviable. In the second experiment, exposure periods of 24, 48 and 72 h to S. marcescens -treated parasitoids produced an increase in S. lepidus mortality of 14, 28 and 38%, respectively. There was 3% successful parasitoid development in weevils exposed for 72 h to parasitoids treated with distilled water. M. aethiopoides has been shown to develop successfully in a wide range of non-target weevil species both in the laboratory and field. Possible reasons for poor survival of M. aethiopoides immature stages in S. lepidus are discussed.     

Predation and the maintenance of color polymorphism in a habitat specialist squamate

Multiple studies have addressed the mechanisms maintaining polymorphism within a population. However, several examples exist where species inhabiting diverse habitats exhibit local population-specific polymorphism. Numerous explanations have been proposed for the maintenance of geographic variation in color patterns. For example, spatial variation in patterns of selection or limited gene flow can cause entire populations to become fixed for a single morph, resulting in separate populations of the same species exhibiting separate and distinct color morphs. The mottled rock rattlesnake (Crotalus lepidus lepidus) is a montane species that exhibits among-population color polymorphism that correlates with substrate color. Habitat substrate in the eastern part of its range is composed primarily of light colored limestone and snakes have light dorsal coloration, whereas in the western region the substrate is primarily dark and snakes exhibit dark dorsal coloration. We hypothesized that predation on high contrast color and blotched patterns maintain these distinct color morphs. To test this we performed a predation experiment in the wild by deploying model snakes at 12 sites evenly distributed within each of the two regions where the different morphs are found. We employed a 2×2 factorial design that included two color and two blotched treatments. Our results showed that models contrasting with substrate coloration suffered significantly more avian attacks relative to models mimicking substrates. Predation attempts on blotched models were similar in each substrate type. These results support the hypothesis that color pattern is maintained by selective predation.     

A test of the thermal coadaptation hypothesis with black rat snakes (Elaphe obsoleta) and northern water snakes (Nerodia sipedon)

• 1.The thermal coadaptation hypothesis predicts that (1) ectotherms experiencing a narrow range of body temperatures in the wild will evolve to perform well over a narrow range of body temperatures and that (2) the optimal temperature for performance will be equal to the preferred body temperature of the species.
• 2.We tested the predictions of the thermal coadaptation hypothesis with black rat snakes (Elaphe obsoleta) and northern water snakes (Nerodia sipedon) because black rat snakes experience lower and more variable body temperatures than northern water snakes at our study site.
• 3.We measured swimming speed, tongue-flicking speed, and striking speed in black rat snakes, and swimming speed and tongue-flicking speed in northern water snakes.
• 4.Adult water snakes generally had narrower performance breadths and higher optimum performance temperatures than adult black rat snakes.
• 5.Performance breadths were the same for swimming, tongue flicking, and striking within adult black rat snakes, but performance optima for these behaviours differed significantly. Performance breadths differed and performance optima were the same for swimming and tongue flicking within adult northern water snakes.
• 6.The relative swimming performance of neonates of the two species was similar in breadth to that of adults, but the thermal optimum for neonate black rat snakes was higher than that of adults.
• 7.Overall, our results provided support for the thermal coadaptation hypothesis.

     

Host plant recognition by the root feeding clover weevil, Sitona lepidus (Coleoptera: Curculionidae)

This study investigated the ability of neonatal larvae of the root-feeding weevil, Sitona lepidus Gyllenhal, to locate white clover Trifolium repens L. (Fabaceae) roots growing in soil and to distinguish them from the roots of other species of clover and a co-occurring grass species. Choice experiments used a combination of invasive techniques and the novel technique of high resolution X-ray microtomography to non-invasively track larval movement in the soil towards plant roots. Burrowing distances towards roots of different plant species were also examined. Newly hatched S. lepidus recognized T. repens roots and moved preferentially towards them when given a choice of roots of subterranean clover, Trifolium subterraneum L. (Fabaceae), strawberry clover Trifolium fragiferum L. (Fabaceae), or perennial ryegrass Lolium perenneL. (Poaceae). Larvae recognized T. repens roots, whether released in groups of five or singly, when released 25 mm (meso-scale recognition) or 60 mm (macro-scale recognition) away from plant roots. There was no statistically significant difference in movement rates of larvae.     

An ultrastructural study of the response of Blatella germanica (Orthoptera: Blattidae) to the nematode Abbreviata caucasica (Spirurida: Physalopteridae)

An ultrastructural study of the response of Blatella germanica (Orthoptera: Blattidae) to the nematode Abbreviata caucasica (Spirurida: Physalopteridea). International Journal for Parasitology4: 133–138. This study investigates the response of the roach, Blatella germanica L. to the invading spirurid nematode, Abbreviata caucasica v. Linstow. Soon after the first stage nematodes entered the epithelial cells of the colon wall, the surrounding host cells broke down into syncytial giant cells. Large polychromatic epithelial cell nuclei occurred throughout the giant cells and the nematodes moved freely within the cytoplasmic matrix. These giant cells were in turn surrounded by blood cells responding to the disruption. The nematodes developed to the infective third stage juveniles within the giant cells and ingested the syncytial cytoplasm. After reaching the third stage, the parasites remained in a quiescent state within the vacuolated cell which was surrounded by a double tissue layer.Evidence indicated that successful development of the parasite was dependent on the disrupted epithelial cells forming a giant syncytial cell which protected and supplied nourishment to the parasite.     

Effects of carbon dioxide on the searching behaviour of the root-feeding clover weevil Sitona lepidus (Coleoptera: Curculionidae)

The respiratory emission of CO2 from roots is frequently proposed as an attractant that allows soil-dwelling insects to locate host plant roots, but this role has recently become less certain. CO2 is emitted from many sources other than roots, so does not necessarily indicate the presence of host plants, and because of the high density of roots in the upper soil layers, spatial gradients may not always be perceptible by soil-dwelling insects. The role of CO2 in host location was investigated using the clover root weevil Sitona lepidus Gyllenhall and its host plant white clover (Trifolium repens L.) as a model system. Rhizochamber experiments showed that CO2 concentrations were approximately 1000 ppm around the roots of white clover, but significantly decreased with increasing distance from roots. In behavioural experiments, no evidence was found for any attraction by S. lepidus larvae to point emissions of CO2, regardless of emission rates. Fewer than 15% of larvae were attracted to point emissions of CO2, compared with a control response of 17%. However, fractal analysis of movement paths in constant CO2 concentrations demonstrated that searching by S. lepidus larvae significantly intensified when they experienced CO2 concentrations similar to those found around the roots of white clover (i.e. 1000 ppm). It is suggested that respiratory emissions of CO2 may act as a 'search trigger' for S. lepidus, whereby it induces larvae to search a smaller area more intensively, in order to detect location cues that are more specific to their host plant.     

New species of Falcaustra (Nematoda: Kathlaniidae) in Nyctimystes cheesmani (Anura: Hylidae) from Papua New Guinea

Falcaustra batrachiensis n. sp. (Ascaridida, Kathlaniidae) from the large intestine of Nyctimystes cheesmani (Anura, Hylidae) is described and illustrated. Falcaustra batrachiensis represents the fifth Australo-Papuan species assigned to the genus and is distinguished from other Australo-Papuan species by the distribution pattern of the caudal papillae (8 precloacal, 2 adcloacal, 6 postcloacal, and 1 median), length of spicules (1.4-1.6 mm) and presence of pseudosuckers (5 or 6). Nyctimystes cheesmani was found to harbor 7 additional species of Nematoda, adults of Cosmocerca novaeguineae, Maxvachonia ewersi, Meteterakis crombiei, Physalopteroides milnensis, Pseudorictularia dipsarilis, Seuratascaris numidica, larvae in cysts of Abbreviata sp., and 1 species of Acanthocephala, Acanthocephalus bufonis. Nyctimystes cheesmani represents a new host record for each of these helminth species.     

New genus of Pharyngodonidae (Nematoda: Oxyuridea) and other helminths in Platymantis nexipus (Anura: Ranidae) from Papua New Guinea

Rokroknema novaebritanniae n. gen., n. sp. (Nematoda: Pharyngodonidae) from the large intestine of Platymantis nexipus (Anura: Ranidae) is described and illustrated. Rokroknema represents the second Australo-Papuan genus assigned to the family Pharyngodonidae known to infect frogs. It is similar to Parathelandros (the other genus), but it is readily distinguished because the posterior pair of caudal papillae is not in the form of a rosette. Platymantis nexipus also was found to harbor 1 species of Digenea, Opisthioglyphe cophixali, and 5 additional species of Nematoda, adults of Aplectana krausi, Cosmocerca novaeguineae, Falcaustra batrachiensis, Icosiella papuensis, and larvae in cysts of Abbreviata sp., plus unidentified cystacanths of 1 species of acanthocephalan.     

Accidental altruism in insular pit-vipers (Gloydius shedaoensis, Viperidae)

Darwinian theory predicts that organisms will display traits that benefit themselves rather than other individuals; exceptions to this rule usually are explicable by kin selection. Our studies on an insular population of venomous snakes in north-eastern China reveal a different situation. Only one species of snake (Gloydius shedaoensis, Viperidae) occurs on the island of Shedao, and displays altruism between size (age) classes. First, small snakes frequently kill prey items larger than they can swallow themselves. This behaviour enhances rates of feeding of larger conspecifics, which scavenge the birds' carcasses. Second, large snakes kill raptorial birds (sparrowhawks Accipiter nisus) that pose little or no threat to themselves. This behaviour reduces predation risk for smaller snakes. These effects are presumably accidental consequences of the high venom toxicity of the pit-vipers, which enable them to kill inedible prey and non-threatening predators at little cost. Nonetheless, this accidental altruism may have significant ecological consequences. For example, these behaviours may contribute to the remarkably high population densities of snakes on Shedao.     

Spauligodon ovifilus n. sp. (Nematoda: Pharyngodonidae) and other helminths from Diplodactylus stenodactylus (Reptilia: Gekkonidae) from Australia

Spauligodon ovifilus n. sp. (Nematoda: Pharyngodonidae) from the large intestines of the gecko Diplodactylus stenodactylus is described and illustrated. Prevalence of infection was 50% (mean intensity 5.9 +/- 6.3, range 1-21). Spauligodon ovifilus n. sp. represents the thirty-fifth species to be assigned to this genus and is distinguished by the extremely long filament of the egg. This is the first report of species of Spauligodon from Australia. In addition, 1 gecko harbored 1 female of Wanaristrongylus papangawurpae, a new host record; 1 gecko harbored 1 encapsulated larva of Abbreviata sp. Review of species assigned to Spauligodon caused the reclassification of Spauligodon azerbajdzanicus to Skrjabinodon azerbajdzanicus n. comb.     

Thermal correlates of foraging-site selection by Chinese pit-vipers (Gloydius shedaoensis,Viperidae)

• 1.Do thermal factors influence foraging-site selection by ectothermic predators? Snake species that obtain their prey from ambush must remain immobile for long periods, precluding overt behavioural thermoregulation; and some “ambush” snakes use thermal cues to detect endothermic prey. Plausibly, alternative ambush sites might differ either in equilibrial body temperatures available to snakes, or in the thermal “background” against which prey items must be detected.
• 2.We examined this topic with field data on pit-vipers (Gloydius shedaoensis) on a small island in northeastern China. Adult snakes feed only on migrating passerine birds. The snakes ambush birds both from arboreal perches (branches of small trees) and from the ground.
• 3.Arboreal versus terrestrial ambush sites differed both in operative temperatures and thermal “backgrounds” available to the snakes. Operative temperatures inside copper models were lower in trees than on the ground (because of wind), and snakes in arboreal ambush sites were cooler than those in terrestrial sites. Thermal backgrounds from arboreal perches were cooler (and thus, provided more contrast against prey items) than did backgrounds available from terrestrial ambush-sites.
• 4.Thermal factors thus modify the suitability of alternative ambush locations for these pit-vipers, but with a trade-off: a snake in a tree can “see” its prey more clearly, but may not be warm enough (and hence, able to strike fast enough) to capture it. Further work is required to determine whether or not snakes actually use such thermal differences as criteria for the selection of ambush sites.

     

Intraspecific aggression, colony identity and foraging distances in Sudanese Microtermes spp. (Isoptera: Termitidae: Macrotermitinae)

Abstract. 1. Intraspecific aggression between termite major workers was used to obtain estimates of foraging distances for three Microtermes species in Sudan.
2. Maximum foraging distance recorded for M. sp. nr albopartitus (Sjöstedt) in Khartoum was 11.3 m, giving an estimated minimum colony area of 100 m². This is probably an underestimate. In the Tokar Delta, individuals from single colonies of M. najdensis Harris were encountered up to 42 m apart, giving a colony area of 1390 m².
3. Intraspecific aggression could not be used reliably to distinguish members of different colonies of M. lepidus Sjöstedt. Soil barrier formation between groups of workers in petri dishes may be of use as a supplementary technique, especially for species showing no clear aggression.
4. Experiments on isolated laboratory colonics of M. sp. Nr lepidus Sjöstedt, established from alates collected in Khartoum, further confirmed the value of inter-colony aggression for indicating colony identity.
5. The complications introduced into estimation of subterranean termite foraging areas by overlap and interdigitation of colonies are discussed.     

Endoparasites in Sphenomorphus jobiensis (Sauria: Scincidae) from Papua New Guinea with description of three new species

One species of digenean, Zeylanurotrema sphenomorphi n. sp., and 2 nematode species, Meteterakis crombiei n. sp. and Physalopteroides milnensis n. sp., from the intestine of Sphenomorphus jobiensis, are described and illustrated. Zeylanurotrema sphenomorphi n. sp. represents the second species, Meteterakis crombiei n. sp. the 18th species, and Physalopteroides milnensis n. sp. the 19th species assigned to each respective genus. In addition, 1 species of cestode, Oochoristica javaensis; 7 nematode species, Abbreviata oligopapillata, Aplectana macintoshii, Aplectana zweifli, Cosmocerca zugi, Maxvachonia adamsoni, Oswaldocruzia bakeri, Parapharyngodon maplestonei; 1 species of acanthocephalan, Acanthocephalus bufonis; and 1 species of pentastome, Kiricephalus sp., were found. With the exception of Abbreviata oligopapillata, Sphenomorphus jobiensis represents a new host record for each species of endoparasite.     

A PRELIMINARY STUDY ON GENUS COMPSIDOLON REUTER 1899 FROM NORTH CHINA (HETEROPTERA: MIRIDAE: PHYLINAE)

Abstract The present paper deals with genus Compsidolon Reuter 1899 from North China. A new species Compsidolon punctulatus sp. nov. is described. C. absinthii (Scott, 1870) is here recorded as new to China, and C; gobicus Nonnaizab 1994 is considered to be a new synonym of Solenoxyphus lepidus (Puton, 1874). Type specimens of the new species will be deposited in the Biological Faculty of Inner Mongolia Teachers' University.     

Anatomical and gravitational influences on cardiac displacement in snakes (Lepidosauria,Serpentes)

Summary Radiographs of live, unanesthetized snakes were used to document the position of the heart in the body cavity during horizontal, head-up, and head-down postures. The extent of cardiac displacement observed during these postural changes differed substantially among the snakes examined, ranging from virtually none in a thin-bodied arboreal snake to as much as three vertebral lengths (=half the length of the heart) in a heavy-bodied terrestrial Crotalus. The basis of this differential cardiac displacement is attributed to the anatomical packaging of the pericardial sac. In some snakes the pericardial sac is loosely suspended in the body cavity by the great vessels and connective tissue sheets. In contrast, in other snakes the pericardial sac is buttressed against the body wall, the lung, or the liver. We hypothesize that cardiac displacement during postural change may alter the pattern of blood flow in the aortae of snakes.     

Two new species of Pharyngodonidae (Nematoda: Oxyuroidea) and other nematodes in Agama caudospina (Squamata: Agamidae) from Kenya, Africa

Parapharyngodon kenyaensis n. sp. and Thelandros samburuensis n. sp. (Nematoda: Pharyngodonidae) from the large intestine of the agamid lizard (Agama caudospina) are described and illustrated. Parapharyngodon kenyaensis n. sp. is the 41st species assigned to the genus, and it differs from other species in that genus by possessing 3 pairs of caudal papillae, cloacal lip adornment, and spicules of 112-120 microm in length. Thelandros samburuensis n. sp. is the 31st species assigned to the genus, and it differs from other species in that genus by possessing swollen posterior annulations, 6 caudal papillae, a smooth anterior cloacal lip, and spicules of 43-52 microm in length. In addition to the 2 new nematode species, Abbreviata ortleppi (Nematoda: Physalopteridae) and Strongyluris ornata (Nematoda: Heterakidae) were found.     

中国北方点翅盲蝽属昆虫初步研究

本文记述了我国北方点翅盲蝽属昆虫Compsidolon Reuterl899,描述了采自于新疆麦盖提县、且末县及墨玉县一新种:斑点翅盲蝽Compsidolon punctulatus sp. nov., 记述了采自青海乌兰县、铜普县及怀头塔拉的中国一新纪录种:灰点翅盲蝽Compsidolon absinthii(Scott 1870),并提出一项新的异名关系:Solenoxyphus lepidus(Puton 1874)=Compsidolon gobicus Nonnaizab l994, syn. nov., 新种模式标本存于内蒙古师范大学生物系。     

中国沟胸盲蝽属新种及新纪录属种记述(半翅目:盲蝽科)(英)

记述了一中国新纪录属,沟胸盲蝽属Solenoxyphus Reuter1875及隶于该属的两新种及一中国新纪录种,分别定名为黄沟胸盲蝽S. flavicans, sp. nov, 采自新疆维吾尔自治区乌鲁木齐市、甘河子县、阜康县,绿沟胸盲蝽S. viridulus, sp. nov.采自青海省乌兰县、新疆维吾尔自治区米泉县、阜康县,及中国新纪录蒿沟胸盲蝽S. lepidus(Puton1874)采自新疆维吾尔自治区乌鲁木齐市、阜康县、米泉县、木垒县及甘河子县,寄主均为蒿属植物Artemisia spp.。     

New genus of Cosmocercidae (nematoda) and other helminths in Hylarana volkerjane (Anura: Ranidae) from papua new Guinea

Paraplesiohedruris rinse n. gen., n. sp. (Ascaridida; Cosmocercoidae; Cosmocercidae) from the large intestine of Hylarana volkerjane (Anura; Ranidae) is described and illustrated. The new genus is assigned to the Cosmocercinae of the Cosmocercidae based on the presence of an esophagus composed of a short pharynx, cylindrical corpus, isthmus, and valved bulb; on the presence in males of paired spicules and numerous caudal papillae; plus the presence in the female of an equatorial vulva, 2 uteri, a short tail, and thin-shelled eggs. The Cosmocercinae now contains 10 genera. Hylarana volkerjane was also found to harbor 6 additional species of Nematoda, adults of Aplectana macintoshii, Icosiella papuensis, Meteterakis crombiei, Paracapillaria spratti, Physalopteroides milnensis, and larvae of Abbreviata sp., as well as 1 species of Acanthocephala, Pseudoacanthocephalus bufonis.     

Phenotypically plastic responses to predation threat in the mangrove rivulus fish (<Emphasis Type="Italic">Kryptolebias marmoratus</Emphasis>): behavior and morphology

Early life environments have important effects on phenotype development, but it can be difficult to disentangle the relative influences of genotype and environment on phenotypic variation within and among populations. Mangrove rivulus fish (Kryptolebias marmoratus) reproduce by self-fertilization and can generate isogenic lineages, which provides opportunities to resolve how the environment shapes the phenotype independent of genetic variation. Rivulus’ ecology is not well understood, but mangrove water snakes (Nerodia clarkii compressicauda) are thought to be a major predator. To test developmental responses to predator-related cues, four rivulus lineages (two that naturally co-exist with snakes; two that do not) were exposed to one of three treatments for 30 days post-hatching: cues from snakes that were fasted, fed rivulus, or fed heterospecifics. One week after exposure, fear and boldness responses were quantified. Individuals were photographed at 2 and 6 months of age for body size, growth, and body shape analysis. Animals that have historically encountered snakes were more risk averse and had wider heads than animals that historically have not encountered snakes. Rivulus exposed to cues from snakes fed conspecifics or heterospecifics grew faster than those exposed to fasted snake cues. Body shape was more streamlined in animals exposed to cues from snakes fed conspecifics, which may facilitate increased jumping performance as a way to escape aquatic predators. Our results suggest that rivulus exhibit phenotypic plasticity in response to cues associated with predator threat and that historical effects from selection or other evolutionary processes also are important determinants of behavioral and morphological variation.