New Thelastomatoidea (Nematoda : Oxyurida) from Australian burrowing cockroaches (Blaberidae : Geoscapheinae, Panesthiinae)

Four new species and two new genera of thelastomatoid are described from several species of Australian burrowing cockroaches (Blattodea: Panesthiinae; Geoscapheinae). Corpicracens munozae n. g., n. sp., Pseudodesmicola botti n. g., n. sp. and Cephalobellus nolani n. sp. are described from Geoscapheus dilatatus (Blattodea: Geoscapheinae) from Mendooran, New South Wales; one new thelastomatid, Blattophila praelongicauda n. sp., is described from Panesthia cribrata from Lamington National Park, Queensland. Corpicracens munozae n. g., n. sp. is long and slender, with a monodelphic female reproductive system, a clavate corpus with a slight posterior pseudobulb, oval eggs flattened at the poles, and a relatively robust, subulate tail. Pseudodesmicola botti n. g., n. sp. is slightly more robust in body, also has a monodelphic reproductive system, a cylindrical corpus with a posterior pseudobulb, ovoid eggs and a very long, subulate tail. Cephalobellus nolani n. sp. is distinguished from other members of the genus by its relatively short and broad body and egg shape. Lastly, Blattophila praelongicauda n. sp. is distinguished from other members of the genus by having eggs with a single, polar operculum, tail length, and position of the vulva, nerve ring and excretory pore. An additional species, known by a single specimen from Panesthia tryoni tryoni from the same locality is characterised but not named. The species found are all relatively rare parasites of Australian burrowing cockroaches, each having a prevalence of less than 10%.

Incubation of turtle eggs at different temperatures: Do embryos compensate for temperature during development?

Freshwater turtle eggs are normally subjected to fluctuations in incubation temperature during natural incubation. Because of this, developing embryos may make physiological adjustments to growth and metabolism in response to incubation at different temperatures. I tested this hypothesis by incubating eggs of the Brisbane river turtle Emydura signata under four different temperature regimes, constant temperatures of 24 degrees C and 31 degrees C throughout incubation, and two swapped-temperature treatments where incubation temperature was changed approximately halfway through incubation. Incubation at 31 degrees C took 42 d, and incubation at 24 degrees C look 78 d, with intermediate incubation periods for the swapped-temperature treatments. Hatchling mass, hatchling size, and total oxygen consumed during development were similar for all incubation regimes. The pattern of oxygen consumption during the last phase of incubation as reflected by rate of increase of oxygen consumption, peak oxygen consumption, and fall in oxygen consumption before hatching was determined solely by the incubation temperature during the last phase of incubation; that is, incubation temperature during the first phase of incubation had no influence on these factors. Thus there is no evidence of temperature compensation in growth or development during embryonic development of E. signata eggs.

Incubation of eggs of the Australian broad-shelled turtle, Chelodina expansa (Testudinata : Chelidae), at different temperatures: effects on pattern of oxygen consumption and hatchling morphology

Incubation temperature influences embryonic development and the morphology of resultant hatchlings in many species of turtle but few studies have addressed its effect on oxygen consumption and total embryonic energy expenditure. Eggs of the Australian broad-shelled river turtle, Chelodina expansa, were incubated at constant temperatures of 24 degrees C and 28 degrees C to determine the effect of temperature on oxygen consumption, embryonic energy expenditure and hatchling morphology. All embryos at both incubation temperatures experienced a period of developmental diapause immediately after oviposition. Once this initial diapause was broken, embryos underwent a further period of developmental arrest when the embryo was still very small and had minimal oxygen consumption (

Application of a species-specific PCR-RFLP to identify Ancylostoma eggs directly from canine faeces

Apart from their veterinary importance, the hookworms Ancylostoma caninum, Ancylostoma braziliense and Ancylostoma caninum are also capable of causing zoonotic disease in humans. A highly sensitive and species-specific PCR-RFLP technique was utilised to detect and differentiate the various canine Ancylostoma spp directly from eggs in faeces. This technique was utilised to screen 101 canine faecal samples from parasite endemic tea growing communities in Assam, India, as part as an ongoing epidemiological investigation into canine parasitic zoonoses. The prevalence of hookworms in dogs was found to be 98% using a combination of PCR and conventional microscopy. Overall, 36% of dogs were found positive for single hookworm infections with A. caninum, 24% positive for single infections with A. braziliense and 38% had mixed infections with both A. caninum and A. braziliense. No dogs were found positive for A. ceylanicum in the community under study. The high prevalence of A. caninum and A. braziliense in dogs in this community may account for the high incidence of cutaneous larva migrans (CLM) observed among the human population residing at the tea estates. The PCR-RFLP technique described herein allows epidemiological screening of canine hookworms to be conducted rapidly, with ease and accuracy, and has the potential to be applied to a number of different clinical, pharmacological and epidemiological situations. (C) 2004 Elsevier B.V. All rights reserved.

Mating behaviour and alternative oviposition sites for male eggs in the heteronomous hyperparasitoid Coccophagus gurneyi Compere (Hymenoptera : Aphelinidae)

The aphelinid parasitoid Coccophagus gurneyi Compere has unusual sex-related host relationships. Females are diploid and develop internally within mealybugs Pseudococcus calceolariae (Maskell). Males, in contrast, are haploid and hyperparasitic, developing on primary parasitoid larvae within the mealybugs. Furthermore, males have been claimed to be capable of either internal or external development, depending on the precise site of deposition of the haploid egg. This diversity of developmental pathways could indicate the existence of a sibling-species complex. We therefore quantified the mating and ovipositional behaviour of C. gurneyi, for comparison with that of an undescribed sibling species. We also checked whether the females deposit male eggs in alternative sites. The pattern of mating was found to be typical of mating behaviour in Coccophagus spp. and was consistent among all mating pairs, suggesting that the colony comprised one species. Further, the mating behaviour was significantly different from that of the undescribed sibling species. The site of male egg deposition varied and is apparently dictated by two factors; whether the mealybug is parasitised and, if so, the size of the parasitoid it contains. If the mealybugs were unparasitised or if the parasitoids within the mealybugs were small (< 0.53 mm), male eggs were deposited within the mealybug haemocoel. If the parasitoids were large (> 1.05 mm), male eggs were deposited within the parasitoids. These results support the claim of alternate host relationships and developmental pathways within males of C. gurneyi.

Development of Trichogramma australicum Girault (Hymenoptera : Trichogrammatidae) in Helicoverpa (Lepidoptera : Noctuidae) host eggs

Morphological studies of development of the egg parasitoid Trichogramma australicum Girault in the cotton bollworm, Helicoverpa armigera (Hubner), were conducted to provide benchmarks for assessing developmental rates in both natural hosts and artificial diets. Observations of living embryos and histological sections show that embryos proceed rapidly through cleavage and blastoderm formation and show a characteristic pinching or rotation 8 h after deposition. Eggs progressively increase in volume, primarily by increasing in diameter at the widest point. At 29 rectangle 1 C the duration of the egg stage is 22-24 h, the larval stage 27 h, the prepupal stage 50-52 h, and pupa 85 h. Larvae undergo dramatic shape changes as they ingest food but do not show signs of larval moults, reinforcing observations that there is only one larval instar. Criteria for staging the embryonic and postembryonic development in natural hosts will be used for future studies aimed at developing and refining artificial diets for Trichogramma.

Incubation of Rigid-shelled Turtle Eggs: do Hydric Conditions Matter?

Rigid-shelled eggs of the broad-shelled river turtle Chelodina expansa were incubated at 28 degreesC in wet (-100 kPa), intermediate (-350 kPa) and dry (-750 kPa) conditions. Incubation period was influenced by clutch of origin, but was independent of incubation water potential. Rates of water gained from the environment and pre-pipping egg mass were influenced by incubation water potential - eggs incubating at higher (less negative) water potentials absorbing more water from their environment. Hatchlings from wet conditions had greater mass but a smaller amount of residual yolk than hatchlings from dry conditions and it is suggested that the amount of yolk converted to tissue is influenced by the amount of water absorbed by the egg during incubation. Water content of yolk-free hatchlings from the -100-kPa treatment was greater than those from the 350-kPa and -750-kPa treatments, but the water content of residual yolks was similar across all hydric conditions.

Tuna fishmeal as a source of DHA for n-3 PUFA enrichment of pork, chicken, and eggs

Enriching foods with long-chain n-3 PUFA (LC n-3 PUFA) is an important approach to increasing the dietary intake of these beneficial nutrients. Enrichment of meat and eggs can be achieved by adding flaxseed, fish oil, or fishmeal to pig or poultry feeds. However, utilization of these sources, particularly fishmeal, has been limited by concerns about adverse effects on sensory qualities, In this study, we evaluated the use of PorcOmega(TM) (POM), a stabilized tuna fishmeal formulation, as a source of DHA for enrichment of park and poultry products, Pigs, broilers, and laying hens were fed rations containing varying levels of POM for varying time periods, and its impact on the LC n-3 PUFA content and sensory qualities of cooked meat and eggs was examined. Pork and chicken products, including chops, sausages, and eggs, with substantially increased (up to sevenfold) levels of LC n-3 PUFA (predominantly DHA) were achieved by including up to 10% POM in rations. The increases were retained after cooking. Some sensory deficits were noted when using higher levels of POM (exceeding 15% in meat and 10% in eggs). However, at modest rates of feeding (5-10% POM), palatable meat and eggs were obtained with worthwhile levels of enrichment. The fishmeal feeding strategy used in this study offers a viable means of producing a range of alternative dietary sources of LC n-3 PUFA. Paper no.

Composition and energy density of eggs from two species of freshwater turtle with twofold ranges in egg size

Lipid, protein, ash, carbohydrate and water content and energy density of eggs were measured from different clutches over a range of egg size in two species of freshwater turtle. Dry egg contents consisted of protein (54-60%), lipid (25-31%) and ash (5-6%) while carbohydrate was found to be negligible (

Structure of the gut contents of Trichogramma australicum Girault (Hymenoptera : Trichogrammatidae) larvae fixed in situ in eggs of its host Helicoverpa armigera (Hubner) (Lepidoptera : Noctuidae)

Trichogramma australicum larvae develop most rapidly in younger eggs of its host, the pest lepidopteran Helicoverpa armigera . To establish how the developmental stage of the host affects the diet of T. australicum , larvae were fixed in situ in eggs of H. armigera of different ages and the structure of the egg contents and parasitoid gut contents examined histologically. Larvae feeding on newly laid host eggs contain primarily yolk particles in their gut, while larvae feeding on older hosts contain necrotic cells and yolk particles. The gut of T. australicum larvae does not contain organised tissue remnants, indicating that larvae feed primarily by sucking food into their pharynx and feed best on a mixture of particulate semisolids in a liquid matrix. Secretory structures of T. australicum larvae that could be involved in modifying the host environment were examined. The hindgut is modified to form an anal vesicle with a number of attributes suggesting that it may be a specialised secretory structure. The paired salivary glands open to the exterior via a common duct.

The effect of parasitization by Trichogramma australicum on Helicoverpa armigera host eggs and embryos

Histological investigations of the pathology of Helicoverpa armigera (Hiibner) eggs after attack by the egg parasitoid, Trichogramma australicum (Girault), indicate that the developing embryo is immediately killed by envenomation. Soon afterward the histological staining characteristics of parasitized host embryos change and the embryonic germ band dissociates into a mass of individual rounded cells. Hosts attacked by females sterilized by gamma-irradiation showed the same pathological effects as normally parasitized hosts, indicating that host degeneration is due to female venom rather than factors derived from the parasitoid embryo or larva. Cell death also occurred in older host embryos although tissue breakdown was delayed. These findings have allowed us to determine not just that the host dies but what happens to the cells and tissues, i.e., their physical appearance, the time course of their degeneration, and that the process is retarded in older hosts. These processes can possibly be emulated in artificial diets. (C) 2003 Elsevier Inc. All rights reserved.

Cannibalistic feeding of larval Trichogramma carverae parasitoids in moth eggs

Wasps of the genus Trichogramma parasitise the eggs of Lepidoptera. They may deposit one or many eggs in each host. Survival is high at low density but reaches a plateau as density increases. To reveal the mechanism by which excess larvae die we chose a lepidopteran host that has flattened, transparent eggs and used video microscopy to record novel feeding behaviours and interactions of larval Trichogramma carverae (Oatman and Pinto) at different densities. Single larvae show a rapid food ingestion phase, followed by a period of extensive saliva release. Ultimately the host egg is completely consumed. The larva then extracts excess moisture from the egg, providing a dry environment for pupation. When multiple larvae are present, the initial scramble for food results in the larvae consuming all of the egg contents early in development. All larvae survive if there is sufficient food for all to reach a threshold developmental stage. If not, physical proximity results in attack and consumption of others, continuing until the surviving larvae reach the threshold stage beyond which attacks seem to be no longer effective. The number of larvae remaining at the end of rapid ingestion dictates how many will survive to emerge as adults.

The Thelastomatoidea (Nematoda : Oxyurida) of two sympatric Panesthiinae (Insecta : Blattodea) from southeastern Queensland, Australia: taxonomy, species richness and host specificity

The thelastomatoid fauna of two species of wood-burrowing cockroach (Blattodea, Blaberidae), Panesthia cribrata and Panesthia tryoni tryoni, from Lamington National Park, Australia, is described. The following eight new species and three new genera of thelastomatid are proposed: Bilobostoma exerovulva n. g., n. sp.; Cordonicola gibsoni n. sp.; Coronostoma australiae n. sp.; Desmicola ornata n. sp.; Hammerschmidtiella hochi n. sp.; Malaspinanema goateri n. g., n. sp.; Travassosinema jaidenae n. sp.; and Tsuganema cribratum n. g., n. sp. Additional data are given for Blattophila sphaerolaima and Leidynemella fusiformis. Of the 11 species reported, nine were found in P. cribrata and ten in P. tryoni tryoni. Such levels of thelastomatoid species richnessness in single host species are exceptional. Only the mole cricket, Gryllotalpa africana (23), and the domestic cockroach, Periplaneta americana (20), have higher reported richness. Three species, T jaidenae, C. australiae and D. ornata, were found either exclusively or significantly more prevalently in P tryoni tryoni than in R cribrata. Species of Travassosinema, Coronostoma and Desmicola have been found previously only in millipedes (Diplopoda), a fact that suggests that there is a greater degree of niche overlap between R tryoni tryoni and millipedes than for R cribrata.