The Evolution of Functionally Redundant Species; Evidence from Beetles

While species fulfill many different roles in ecosystems, it has been suggested that numerous species might actually share the same function in a near neutral way. So-far, however, it is unclear whether such functional redundancy really exists. We scrutinize this question using extensive data on the world’s 4168 species of diving beetles. We show that across the globe these animals have evolved towards a small number of regularly-spaced body sizes, and that locally co-existing species are either very similar in size or differ by at least 35%. Surprisingly, intermediate size differences (10–20%) are rare. As body-size strongly reflects functional aspects such as the food that these generalist predators can eat, these beetles thus form relatively distinct groups of functional look-a-likes. The striking global regularity of these patterns support the idea that a self-organizing process drives such species-rich groups to self-organize evolutionary into clusters where functional redundancy ensures resilience through an insurance effect

Evolution of Blind Beetles in Isolated Aquifers: A Test of Alternative Modes of Speciation

Evidence is growing that not only allopatric but also sympatric speciation can be important in the evolution of species. Sympatric speciation has most convincingly been demonstrated in laboratory experiments with bacteria, but field-based evidence is limited to a few cases. The recently discovered plethora of subterranean diving beetle species in isolated aquifers in the arid interior of Australia offers a unique opportunity to evaluate alternative modes of speciation. This naturally replicated evolutionary experiment started 10-5 million years ago, when climate change forced the surface species to occupy geographically isolated subterranean aquifers. Using phylogenetic analysis, we determine the frequency of aquifers containing closely related sister species. By comparing observed frequencies with predictions from different statistical models, we show that it is very unlikely that the high number of sympatrically occurring sister species can be explained by a combination of allopatric evolution and repeated colonisations alone. Thus, diversification has occurred within the aquifers and likely involved sympatric, parapatric and/or microallopatric speciation

The evolution of epigean and stygobitic species of Koonunga Sayce, 1907 (Syncarida: Anaspidacea) in Southern Australia, with the description of three new species

Three new species of Koonunga were discovered in surface and subterranean waters in southern Australia, and were defined using mtDNA analyses and morphology. The new species are: Koonunga hornei Leijs & King; K. tatiaraensis Leijs & King and K. allambiensis Leijs & King. Molecular clock analyses indicate that the divergence times of the species are older than the landscape that they currently inhabit. Different scenarios explaining this apparent discrepancy are discussed in the context of the palaeography of the area. A freshwater epigean origin for Koonunga is considered the most likely hypothesis, whereby some lineages made the transition to the subterranean environment within the last few million years influenced by significant climatic cooling/drying. We discuss the possibility that one stygobitic lineage secondarily regained some of its body pigmentation as adaptation to increased photic conditions after cave collapse and forming of cenotes during the last glacial maximum.Remko Leijs, Tessa Bradford, James G. Mitchell, William F. Humphreys, Steven J. B. Cooper, Peter Goonan, Rachael A. Kin

Sociality and the rate of molecular evolution

Copyright © The Author 2005. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved.The molecular clock does not tick at a uniform rate in all taxa but may be influenced by species characteristics. Eusocial species (those with reproductive division of labor) have been predicted to have faster rates of molecular evolution than their nonsocial relatives because of greatly reduced effective population size; if most individuals in a population are nonreproductive and only one or few queens produce all the offspring, then eusocial animals could have much lower effective population sizes than their solitary relatives, which should increase the rate of substitution of "nearly neutral" mutations. An earlier study reported faster rates in eusocial honeybees and vespid wasps but failed to correct for phylogenetic nonindependence or to distinguish between potential causes of rate variation. Because sociality has evolved independently in many different lineages, it is possible to conduct a more wide-ranging study to test the generality of the relationship. We have conducted a comparative analysis of 25 phylogenetically independent pairs of social lineages and their nonsocial relatives, including bees, wasps, ants, termites, shrimps, and mole rats, using a range of available DNA sequences (mitochondrial and nuclear DNA coding for proteins and RNAs, and nontranslated sequences). By including a wide range of social taxa, we were able to test whether there is a general influence of sociality on rates of molecular evolution and to test specific predictions of the hypothesis: (1) that social species have faster rates because they have reduced effective population sizes; (2) that mitochondrial genes would show a greater effect of sociality than nuclear genes; and (3) that rates of molecular evolution should be correlated with the degree of sociality. We find no consistent pattern in rates of molecular evolution between social and nonsocial lineages and no evidence that mitochondrial genes show faster rates in social taxa. However, we show that the most highly eusocial Hymenoptera do have faster rates than their nonsocial relatives. We also find that social parasites (that utilize the workers from related species to produce their own offspring) have faster rates than their social relatives, which is consistent with an effect of lower effective population size on rate of molecular evolution. Our results illustrate the importance of allowing for phylogenetic nonindependence when conducting investigations of determinants of variation in rate of molecular evolution.Lindell Bromham and Remko Ley

New species of Goniocolletes and Trichocolletes (Hymenoptera, Colletidae) from southern Australia

Goniocolletes comatus Maynard, 2013 is redescribed. G. wanni sp. n. and the male of Trichocolletes luteorufus Batley & Houston, 2012 are described

A morphological and molecular study of some species in the Camponotus maculatus group (Hymenoptera: Formicidae) in Australia and Africa, with a description of a new Australian species

Copyright © 2006 Austrian Society of EntomofaunisticsArchie J. McArthur & Remko Ley

Figure 20-21 from: Leijs R, Batley M, Hogendoorn K (2017) The genus Amegilla (Hymenoptera, Apidae, Anthophorini) in Australia: A revision of the subgenera Notomegilla and Zonamegilla. ZooKeys 653: 79-140. https://doi.org/10.3897/zookeys.653.11177

Figure 20-21 - S6 of males 20 Notomegilla 21 Zonamegilla

Systematics and evolution of the Australian subterranean hydroporine diving beetles (Dytiscidae), with notes on Carabhydrus

© CSIRO 2008Calcrete aquifers of the Yilgarn area of Western Australia and the Ngalia Basin, Northern Territory, Australia are known to contain a rich invertebrate stygofauna, including the world’s most diverse assemblage of subterranean diving beetles. Here we determine the generic relationships of these subterranean diving beetle species in the tribe Hydroporini and assess their evolutionary origins. Phylogenetic analyses of 1642 base pairs of mitochondrial DNA (mtDNA), comprising segments of CO1, 16S rRNA, tRNAleu and ND1 genes, revealed that the subterranean species from the arid zone, previously classified under the genus Nirripirti Watts & Humphreys (Hydroporini), are all closely related to the genus Paroster Sharp. We synonymise the stygobitic genus Nirripirti with the genus Paroster. Factors that may have been important for the transitions to stygobitic life such as historical and contemporary species distributions, reproductive ecology and body size are discussed. We show that pre-adaptations such as preference for temporary, but seasonally reliable, water and preference to live among gravel and sand along running water would have favoured transitions from surface to stygobitic life, but that large body size may have restricted the likelihood of successful transitions.Remko Leys and Chris H. Watt

Bogidiella Venetris,a new species of subterranean Amphipoda (Bogidiellidae) from Australia, with remarks on the systematics and biogeography

A new species of subterranean amphipod, Bogidiella veneris, from Venus Bay, South Australia is described. The species was found in a groundwater observation well drilled in an aeolianite limestone formation only 500 m from the seashore. The discovery of the new bogidiellid amphipod is one of the outcomes of a three year stygofauna survey in South Australia. Bogidiella veneris is the fourth species of Bogidiellidae from the Australian region.Remko Leijs, Armin Bloechl, and Stefan Koeneman

The genus Amegilla (Hymenoptera, Apidae, Anthophorini) in Australia: a revision of the subgenus Asaropoda

The species in the subgenus Amegilla (Asaropoda) are revised. Species delineation was decided based on diagnostic morphological characters as well as an incomplete phylogeny based on mitochondrial cytochrome oxidase 1 sequence data. Strong support was obtained for separating the Australian species of Amegilla into the three subgenera previously proposed on the basis of morphology. The subgenus Asaropoda was found to comprise 21 species, including ten new species: A. albiclypeata Leijs, sp. nov., A. aurantia Leijs, sp. nov., A. batleyi Leijs, sp. nov., A. crenata Leijs, sp. nov., A. griseocincta Leijs, sp. nov., A. incognita Leijs, sp. nov., A. nitidiventris Leijs, sp. nov., A. scoparia Leijs, sp. nov., A. xylocopoides Leijs, sp. nov., and A. youngi Leijs, sp. nov. The subspecies A. preissi frogatti is raised to species level, and 16 new synonymies are proposed. Keys to the species of both sexes and descriptions or redescriptions are provided. Distribution maps, data on flower visitation and phenology are given