Exoskeletons characterise Arthropoda and have allowed the morphological and taxonomic diversity of the phylum. Exoskeletal sclerotisation occurs in genetically designated regions, and mandibles represent one such area of high sclerotisation.Mandible morphology reflects dietary preferences and niche partitioning and has therefore been well documented. However, mandibular cuticular microstructure has been under-documented. Here we use scanning electron microscopy to explore mandible microstructure in four disparate Australian Formicidae taxa (ants) with different life modes and diets: Camponotus nigriceps, Iridomyrmex purpureus, Odontomachus simillimus and Rhytidoponera aciculata. We test the hypothesis that mandible construction is highly conserved across these species, as would be expected for arthropod cuticle. We show broadly similar mandible microstructure but report that pore canals and cuticular indentations are not ubiquitous among all studied taxa.Our preliminary results demonstrate that ant taxa have morphologically plastic mandibles with a highly conserved construction, potentially reflecting an interesting record of evolutionary stasis.
Tasmanian populations of the eastern quoll Dasyurus viverrinus, which represent the last wild stronghold of this species after its extirpation from the Australian mainland, have experienced declines of more than 50% over the past three decades. In this pilot study, we investigate the feasibility of supplementing wild populations with captive-bred individuals to attempt to reverse observed declines. Our results are encouraging, in that we recorded high initial survival and low initial dispersal of captive-bred individuals relative to previous release attempts in mainland Australia. Further work is ongoing to determine longterm survival of released individuals and the genetic and population-level impacts on local populations. Our preliminary results support the use of population supplementation as an effective conservation action, which allows for early intervention to address species declines while simultaneously testing hypotheses about their underlying causes.
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