186 research outputs found

    Formyltetrahydrofolate Synthetase Gene Diversity in the Guts of Higher Termites with Different Diets and Lifestyles

    Get PDF
    In this study, we examine gene diversity for formyl-tetrahydrofolate synthetase (FTHFS), a key enzyme in homoacetogenesis, recovered from the gut microbiota of six species of higher termites. The "higher" termites (family Termitidae), which represent the majority of extant termite species and genera, engage in a broader diversity of feeding and nesting styles than the "lower" termites. Previous studies of termite gut homoacetogenesis have focused on wood-feeding lower termites, from which the preponderance of FTHFS sequences recovered were related to those from acetogenic treponemes. While sequences belonging to this group were present in the guts of all six higher termites examined, treponeme-like FTHFS sequences represented the majority of recovered sequences in only two species (a wood-feeding Nasutitermes sp. and a palm-feeding Microcerotermes sp.). The remaining four termite species analyzed (a Gnathamitermes sp. and two Amitermes spp. that were recovered from subterranean nests with indeterminate feeding strategies and a litter-feeding Rhynchotermes sp.) yielded novel FTHFS clades not observed in lower termites. These termites yielded two distinct clusters of probable purinolytic Firmicutes and a large group of potential homoacetogens related to sequences previously recovered from the guts of omnivorous cockroaches. These findings suggest that the gut environments of different higher termite species may select for different groups of homoacetogens, with some species hosting treponeme-dominated homoacetogen populations similar to those of wood-feeding, lower termites while others host Firmicutes-dominated communities more similar to those of omnivorous cockroaches

    Comparative morphological trade-offs between pre- and post-copulatory sexual selection in Giant hissing cockroaches (Tribe: Gromphadorhini)

    Get PDF
    Sperm competition theory predicts that animals face a trade-off between investment in weaponry and investment in ejaculate composition. Within the Madagascan giant hissing cockroaches (Tribe Gromphadorhini) differences in morphology exist that may indicate differing strategies of male-male competition. We compared relative pronotal horn length using high-resolution X-ray CT scanning data, relative testes mass, and male-male agonistic behaviour between two species of hissing cockroaches, Gromphadorhina oblongonota and Aeluropoda insignis. The gross morphology and behaviour of these two species indicated that G. oblongonota is selected for pre-copulatory mate acquisition and that A. insignis is selected for post-copulatory sperm competition. We found evidence for a trade-off when investing in testes mass vs. horn length between the species. The large, aggressive G. oblongonota follows a strategy of greater investment in weapons at the expense of testes mass while the smaller, less-aggressive A. insignis invests in relatively greater testes mass and less in pronotal weapon length. We also found evidence of a trade-off within each species, where individuals invest more heavily in weapon length at the expense of testes mass. These findings support the predictions of pre- and postcopulatory competitive investment trade-offs for a relatively understudied Tribe of cockroaches

    Factor H autoantibody is associated with atypical hemolytic uremic syndrome in children in the United Kingdom and Ireland

    Get PDF
    Factor H autoantibodies can impair complement regulation, resulting in atypical hemolytic uremic syndrome, predominantly in childhood. There are no trials investigating treatment, and clinical practice is only informed by retrospective cohort analysis. Here we examined 175 children presenting with atypical hemolytic uremic syndrome in the United Kingdom and Ireland for factor H autoantibodies that included 17 children with titers above the international standard. Of the 17, seven had a concomitant rare genetic variant in a gene encoding a complement pathway component or regulator. Two children received supportive treatment; both developed established renal failure. Plasma exchange was associated with a poor rate of renal recovery in seven of 11 treated. Six patients treated with eculizumab recovered renal function. Contrary to global practice, immunosuppressive therapy to prevent relapse in plasma exchange–treated patients was not adopted due to concerns over treatment-associated complications. Without immunosuppression, the relapse rate was high (five of seven). However, reintroduction of treatment resulted in recovery of renal function. All patients treated with eculizumab achieved sustained remission. Five patients received renal transplants without specific factor H autoantibody–targeted treatment with recurrence in one who also had a functionally significant CFI mutation. Thus, our current practice is to initiate eculizumab therapy for treatment of factor H autoantibody–mediated atypical hemolytic uremic syndrome rather than plasma exchange with or without immunosuppression. Based on this retrospective analysis we see no suggestion of inferior treatment, albeit the strength of our conclusions is limited by the small sample siz

    Susceptibility of European <em>Agrilus</em> beetle species to the biocontrol agents of Emerald Ash Borer in the laboratory

    Get PDF
    \ua9 2024. The emerald ash borer (EAB, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) is devastating ash trees in its invaded range of North America and spreading rapidly towards Western Europe from European Russia and Ukraine. To allow a rapid response when the beetle is detected, slow its spread and protect trees as part of a wider integrated pest management programme, pre-emptive biological control strategies that are suitable for Great Britain and the rest of Europe must urgently be developed. Three classical hymenopteran biological control agents have been mass-reared and released within North America to control EAB: the egg parasitoid Oobius agrili Zhang and Huang (Hymenoptera: Encyrtidae), and the larval parasitoids Tetrastichus planipennisi and Spathius galinae Belokobylskij &amp; Strazanac (Hymenoptera: Braconidae). This study presents data on the risk these parasitoid wasps might pose to British Agrilus beetles. “No-choice” laboratory assays tested the susceptibility of A. biguttatus Fabricus eggs and larvae and A. sulcicollis Lacordaire and A. convexicollis Redtenbacher eggs to the parasitoids. Oobius agrili, T. planipennisi and S. galinae all attacked A. biguttatus, and offspring were produced. Oobius agrili also attacked the eggs of A. convexicollis, but not A. sulcicollis. This study is the first to show parasitism of a non-target species by T. planipennisi. Further work is needed to fully assess the non-target risk of these parasitoids for release using more ecologically relevant tests, such as ‘choice’, semi-field and chemical ecology assays on the attacked Agrilus species

    Investigating the threat to Sitka spruce from Ips typographus: discrimination and colonization of Britain's principal commercial conifer by a damaging forest pest

    Get PDF
    BACKGROUND: Ips typographus (L.), the eight-toothed spruce bark beetle (Coleoptera: Scolytinae), has devastated European Norway spruce (Picea abies) forests in recent years. For the first time, I. typographus has established localised breeding populations in Britain, where Sitka spruce (P. sitchensis) is a critical component of plantation forestry. The interactions between Norway spruce and I. typographus are well understood, but relatively little is known about the susceptibility of Sitka spruce to the beetle. This study aimed to determine whether I. typographus would select Sitka, compared to Norway spruce, as a host for breeding, and to study the chemical ecology underlying these host preferences. RESULTS: Host choice assays were conducted in the laboratory using freshly cut spruce logs, and then verified in the field in an area with an endemic population of I. typographus. Overall, colonisation and breeding success were found to be similar in cut Sitka and Norway spruce material. The response of I. typographus, reared on both Norway and Sitka spruce, to headspace extracts of aged and fresh Norway and Sitka spruce billets was tested behaviourally using four-arm olfactometry. Odours of aged wood from the two species were equally attractive, and fresh Sitka was more attractive than fresh Norway spruce. Antennal responses to Norway Spruce and Sitka Spruce billet headspace extracts were located using GC-EAG and identified by coupled GC-mass spectrometry and GC co-injection with authentic standards. Norway- and Sitka spruce-reared beetles did not differentiate between synthetic Norway or Sitka spruce blends and responded similarly. CONCLUSION: These findings suggest I. typographus will select and colonise cut Sitka as readily as cut Norway spruce, with implications for its establishment risk in Sitka-growing regions. The study advances the understanding of the role of both host-emitted volatile organic compounds (VOCs) and induced host preference in host selection by I. typographus
    corecore