Biology subjects

Proctor, H.

Publications and source records attributed to Proctor, H..

4 recordsLinked to original sources

bioRxiv2023

Host space, not energy or symbiont size, constrains feather mite abundance across passerine bird species

Comprehending symbiont abundance among host species is a major ecological endeavour, and the metabolic theory of ecology has been proposed to understand what constraints symbiont populations. We parameterized metabolic theory equations to predict how bird species body size and the body size of their feather mites relate to mite abundance according to four potential energy (microbial abundance, uropygial gland size) and space constraints (wing area, number of feather barbs). Predictions were compared with the empirical scaling of feather mite abundance from 26,604 birds of 106 passerine species, using phylogenetic modelling and quantile regression. Feather mite populations were strongly constrained by host space (number of feather barbs) and not energy. Moreover, feather mite species body size was unrelated to their abundance or to the body size of their host species. We discuss the implications of our results for our understanding of the bird-feather mite system and for symbiont abundance in general.

ecology↗

bioRxiv2021

Mating duration and prolonged post-copulatory associations in Arrenurus water mites (Actinotrichida: Parasitengonina: Hydrachnidiae)

Conflicts of interest between the sexes over control of mating can be reflected in various aspects of morphology and behaviour, including structure of genitalia and copulation duration. In Arrenurus water mites (Hydrachnidia: Arrenuridae) there are two main patterns of sperm transfer that differ in degree of potential male control of sperm uptake by females. In some species, males are equipped with an intromittent organ (the petiole) that is used to forcefully insert sperm into the female reproductive tract. In others, males lack an intromittent organ and females appear to push sperm into their reproductive opening themselves. Theory suggests that the amount of time spent in courtship after sperm transfer should differ between males with and without an intromittent structure. We predicted that male Arrenurus able to push sperm into the females reproductive tract (petiolate males) should spend less time courting females after transferring sperm than apetiolate males, which may have to convince females to take up their sperm. Here, we examined durations of mating for 10 species of Arrenurus with males that differ in genital morphology: six species with males equipped with a well developed petiole (= petiolate species) and four species with males that either completely lack a petiole or have a minute peg-like petiole that does not appear to function as an intromittent organ (= apetiolate species). We tested whether males of petiolate species spend less time in the stage of courtship that takes place after sperm transfer (= post-transfer courtship) than apetiolate males. In contrast to our prediction, we found that species with well developed petioles spent significantly more time in post-transfer behaviours than species lacking petioles. The possible function of protracted post-transfer courtship in the genus Arrenurus is discussed.

evolutionary biology↗

bioRxiv2021

Species boundaries among extremely diverse and sexually dimorphic Arrenurus water mites (Acariformes: Hydrachnidiae: Arrenuridae)

Arrenurus (Arrenuridae) is the most species-rich genus of mites with about 950 named species that inhabit standing, and to a lesser extent, running water habitats around the world. To date, distinguishing species of Arrenurus has been based on male reproductive morphology. Here, we use morphological and molecular approaches to examine species boundaries among 42 named species of Arrenurus, including four named species that have colour variants (red and green A. americanus, and red and blue A. intermedius, A. manubriator and A. apetiolatus), and two unnamed morphospecies. In this study, we examine male genital structures with the use of SEM techniques, and apply mitochondrial (COI barcode region) and nuclear (28S rRNA) gene fragments to test whether male morphology reflects species boundaries in Arrenurus assessed by molecular analyses. Our results reveal that male reproductive morphology parallels species boundaries as judged by molecular data. We discuss the cases of genetically poorly diversified, yet morphologically clearly defined named species. Moreover, we show that based on the species we examined, colour morphs within otherwise morphologically similar specimens represent within-species variation and, in the absence of other diagnostic traits, colour itself can be misleading in distinguishing species. Our outcomes on molecular taxonomy of Arrenurus provide a background for testing hypotheses about speciation rate in water mites.

zoology↗

bioRxiv2017

The Parasite Extinction Assessment & Red List: an open-source, online biodiversity database for neglected symbionts

Parasite conservation is a rapidly growing field at the intersection of ecology, epidemiology, parasitology, and public health. The overwhelming diversity of parasitic life on earth, and recent work showing that parasites and other symbionts face severe extinction risk, necessitates infrastructure for parasite conservation assessments. Here, we describe the release of the Parasite Extinction Assessment & Red List (PEARL) version 1.0, an open-access database of conservation assessments and distributional data for almost 500 macroparasitic invertebrates. The current approach to vulnerability assessment is based on range shifts and loss from climate change, and will be expanded as additional data (e.g., host-parasite associations and coextinction risk) is consolidated in PEARL. The web architecture is also open-source, scalable, and extensible, making PEARL a template for more eZcient red listing for other high-diversity, data-de1cient groups. Future iterations will also include new functionality, including a user-friendly open data pository and automated assessment and re-listing.

ecology↗