Population dynamics and pathogens of the invasive yellow crazy ant (Anoplolepis gracilipes) in Arnhem Land, Australia

10.26686/wgtn.17014115.v1 ◽

2021 ◽

Author(s):

◽

Meghan Dawn Cooling

Keyword(s):

Introduced Species ◽

Large Scale ◽

Reproductive Output ◽

Egg Laying ◽

Population Declines ◽

Queen Number ◽

Invasive Ant ◽

Anoplolepis Gracilipes ◽

Population Type ◽

Arnhem Land

<p>Though many populations of introduced species have been observed to collapse, the reasons behind these declines are seldom investigated. Anoplolepis gracilipes is considered among one of the top six most economically and ecologically damaging invasive ant species in the world. However, introduced populations of A. gracilipes have been observed to decline. My overall aims in this thesis were to document A. gracilipes population declines, to investigate the possibility that pathogens were playing a role in the observed population declines, and to identify putative pathogens infecting A. gracilipes as potential candidates for biocontrol agents. I documented the observed A. gracilipes population declines that were the driving force for this project. I detailed large-scale reductions in the spatial extent of four populations with before and after survey data. I also presented data on three populations that were recorded as present, but disappeared before they could be spatially delimited. I speculated on the possible reasons for these declines and explained why I do not think other explanations are likely. I then investigated the hypothesis that a pathogen or parasite is affecting A. gracilipes queens in declining Arnhem Land populations. I did this in three ways: 1) based on preliminary findings, I looked at the effect of an artificial fungal infection on A. gracilipes reproduction. I compared reproductive output between control colonies and those treated with either a fungal entomopathogen (Metarhizium anisopliae) or fungicidal antibiotics. There was no correlation between either treatment and the number of eggs, larvae, pupae or males a colony produced after 70 days. I found queen number had no effect on colony reproductive output, suggesting that queens are able to adjust their egg-laying rate in the presence of other queens. I found no evidence that M. anisopliae affected reproductive output at the tested concentrations; 2) I explored the hypothesis that a pathogen that kills or affects the reproductive output of A. gracilipes queens is the mechanism or reason behind the population declines. I measured queen number per nest, egg-laying rate, fecundity and fat content and compared them between sites in different stages of decline or expansion (population types, consisting of low, medium and high-density populations). I discovered that 23% of queens had melanized nodules, a cellular immune response in insects, in their ovaries or fat bodies. The presence of nodules was correlated with a 22% decrease in the number of oocytes per ovary; however, nodule presence was not associated with population type, suggesting that though there are clearly pathogens or parasites capable of penetrating the cuticle of A. gracilipes, they are unlikely to be responsible for the observed population declines; 3) I compared microbial communities (bacteria and viruses) between queens from different population types. I found viral sequences that match to the Dicistroviridae family of viruses in low and medium-density populations. I found no differences in bacterial community structure between population types. The presence of sequences similar to the entomopathogens Rhabdochlamydia and Serratia marcescens, as well as the reproductive parasite Cardinium in A. gracilipes, deserves further investigation. Though introduced species’ populations have been observed to decline, this is one of the first studies to quantitatively examine, document, and investigate a mechanism behind such a decline. Understanding the mechanisms by which an invader declines may have important implications for invasive ant management worldwide.</p>

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Indirect evidence of pathogen-associated altered oocyte production in queens of the invasive yellow crazy ant, Anoplolepis gracilipes, in Arnhem Land, Australia

Bulletin of Entomological Research ◽

10.1017/s0007485317000967 ◽

2017 ◽

Vol 108 (4) ◽

pp. 451-460 ◽

Cited By ~ 3

Author(s):

M.D. Cooling ◽

B.D. Hoffmann ◽

M.A.M. Gruber ◽

P.J. Lester

Keyword(s):

Reproductive Output ◽

Indirect Evidence ◽

Pathogenic Microorganism ◽

Queen Number ◽

Invasive Ant ◽

Anoplolepis Gracilipes ◽

Significant Difference ◽

Arnhem Land ◽

Fat Bodies ◽

Cellular Immune

AbstractAnoplolepis gracilipes is one of the six most widespread and pestiferous invasive ant species. Populations of this invader in Arnhem Land, Australia have been observed to decline, but the reasons behind these declines are not known. We investigated if there is evidence of a pathogen that could be responsible for killing ant queens or affecting their reproductive output. We measured queen number per nest, fecundity and fat content of queens from A. gracilipes populations in various stages of decline or expansion. We found no significant difference in any of these variables among populations. However, 23% of queens were found to have melanized nodules, a cellular immune response, in their ovaries and fat bodies. The melanized nodules found in dissected queens are highly likely to indicate the presence of pathogens or parasites capable of infecting A. gracilipes. Queens with nodules had significantly fewer oocytes in their ovaries, but nodule presence was not associated with low ant population abundances. Although the microorganism responsible for the nodules is as yet unidentified, this is the first evidence of the presence of a pathogenic microorganism in the invasive ant A. gracilipes that may be affecting reproduction.

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Snake charming and the exploitation of snakes in Morocco

Oryx ◽

10.1017/s0030605316000910 ◽

2016 ◽

Vol 52 (2) ◽

pp. 374-381 ◽

Cited By ~ 1

Author(s):

Juan M. Pleguezuelos ◽

Mónica Feriche ◽

José C. Brito ◽

Soumía Fahd

Keyword(s):

Reproductive Output ◽

Surveys And Questionnaires ◽

Market Price ◽

Tourism Industry ◽

Cultural Dimensions ◽

Population Declines ◽

Field Surveys ◽

Focal Species ◽

The Impact ◽

Naja Haje

AbstractTraditional activities that potentially threaten biodiversity represent a challenge to conservationists as they try to reconcile the cultural dimensions of such activities. Quantifying the impact of traditional activities on biodiversity is always helpful for decision making in conservation. In the case of snake charming in Morocco, the practice was introduced there 500 years ago by the religious order the Aissawas, and is now an attraction in the country's growing tourism industry. As a consequence wild snake populations may be threatened by overexploitation. The focal species for snake charming, the Egyptian cobra Naja haje, is undergoing both range and population declines. We estimated the level of exploitation of snakes based on field surveys and questionnaires administered to Aissawas during 2003–2014, and compared our results with those of a study conducted 25 years previously. Aissawas use four venomous and four non-venomous species for snake charming and we estimate they harvest a minimum of 4,500 individuals annually, mostly venomous snakes. For exhibition purposes they selectively remove the largest specimens from the wild (i.e. those that could have the highest reproductive output). Compared to the previous data, we detected (1) a reduction in the number of species collected, (2) an increased distance to collecting fields, and (3) an increase in the market price for snakes, after correction for accumulated inflation, signifying a higher demand for these animals.

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From individual to population level: Temperature and snow cover modulate fledging success through breeding phenology in greylag geese (Anser anser)

Scientific Reports ◽

10.1038/s41598-021-95011-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Didone Frigerio ◽

Petra Sumasgutner ◽

Kurt Kotrschal ◽

Sonia Kleindorfer ◽

Josef Hemetsberger

Keyword(s):

Ambient Temperature ◽

Reproductive Output ◽

Population Level ◽

Egg Laying ◽

Future Research ◽

Breeding Phenology ◽

Anser Anser ◽

Fledging Success ◽

Average Annual Temperature ◽

Greylag Geese

AbstractLocal weather conditions may be used as environmental cues by animals to optimize their breeding behaviour, and could be affected by climate change. We measured associations between climate, breeding phenology, and reproductive output in greylag geese (Anser anser) across 29 years (1990–2018). The birds are individually marked, which allows accurate long-term monitoring of life-history parameters for all pairs within the flock. We had three aims: (1) identify climate patterns at a local scale in Upper Austria, (2) measure the association between climate and greylag goose breeding phenology, and (3) measure the relationship between climate and both clutch size and fledging success. Ambient temperature increased 2 °C across the 29-years study period, and higher winter temperature was associated with earlier onset of egg-laying. Using the hatch-fledge ratio, average annual temperature was the strongest predictor for the proportion of fledged goslings per season. There is evidence for an optimum time window for egg-laying (the earliest and latest eggs laid had the lowest fledging success). These findings broaden our understanding of environmental effects and population-level shifts which could be associated with increased ambient temperature and can thus inform future research about the ecological consequences of climate changes and reproductive output in avian systems.

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Research and industrialisation of Hermetia illucens L. in China

Journal of Insects as Food and Feed ◽

10.3920/jiff2019.0020 ◽

2020 ◽

Vol 6 (1) ◽

pp. 5-12

Author(s):

J.B. Zhang ◽

J.K. Tomberlin ◽

M.M. Cai ◽

X.P. Xiao ◽

L.Y. Zheng ◽

...

Keyword(s):

Large Scale ◽

Organic Waste ◽

Animal Feed ◽

Egg Laying ◽

Breeding Method ◽

Hermetia Illucens ◽

Cold Temperatures ◽

The Usa ◽

The Government ◽

Future Work

The larvae of the black soldier fly (BSF), Hermetia illucens L., are commonly associated with decaying organic wastes. Over the past 15 years, investigators in China have conducted extensive research exploring the use of BSF larvae to recycle organic materials as a means to protect the environment, while producing products of value, such as protein and bioenergy. Initial efforts were based on a BSF strain from the USA. However, since then, H. illucens strains from specimens collected in Hubei and Guangdong Provinces have been established and used as models to explore the use of this species in sustainable agriculture. China has played an instrumental role in developing an in-door breeding method using a quartz-iodine lamp rather than depend on natural sunlight. This discovery has allowed the establishment of in-door BSF colonies in regions throughout the world where abiotic conditions (i.e. cold temperatures) are preventative. Researchers in China paved the way for using microbes as a means to enhance BSF production including, enhancing BSF egg-laying as well as waste reduction. Furthermore, bacteria from BSF gut or waste can be cultured and used to promote BSF growth, shorten conversion time, and enhanced conversion efficacy. Recent efforts have demonstrated BSF larvae can degrade antibiotics as well as suppress noxious odours in livestock manure. Due to the efforts of research on BSF in China, numerous companies that recycle organic waste at a large scale (>20 tonnes waste digested/day), have been established. Resulting products include insect powder, and live BSFL that can be used as animal feed ingredients for livestock (e.g. eels and frogs), while protecting the environment. Future work will decipher the mechanisms regulating BSF larval conversion of organic waste so that the system can be optimised. However, efforts are still needed at the government level to establish quality assurance standards if this process is truly to become established as an industry in China.

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Distinct colony boundaries and larval discrimination in polygyne red imported fire ants (Solenopsis invicta)

10.22541/au.163251827.70085127/v1 ◽

2021 ◽

Author(s):

MacKenzie Kjeldgaard ◽

Pierre-André Eyer ◽

Collin McMichael ◽

Alison Bockoven ◽

Joanie King ◽

...

Keyword(s):

Solenopsis Invicta ◽

Sucrose Solution ◽

Ecological Impact ◽

Egg Laying ◽

Fire Ants ◽

Fire Ant ◽

Red Imported Fire Ant ◽

Invasive Ant ◽

Nestmate Discrimination ◽

Social Forms

Evaluating the factors that promote invasive ant abundance is critical to assess their ecological impact and inform their management. Many invasive ant species show reduced nestmate recognition and an absence of boundaries between unrelated nests, which allow populations to achieve greater densities due to reduced intraspecific competition. We examined nestmate discrimination and colony boundaries in introduced populations of the red imported fire ant (Solenopsis invicta; hereafter, fire ant). Fire ants occur in two social forms: monogyne (colonies with a single egg-laying queen) and polygyne (colonies with multiple egg-laying queens). In contrast with monogyne nests, polygyne nests are thought to be interconnected due to the reduced antagonism between non-nestmate polygyne workers, perhaps because polygyne workers habituate the colony to an odor unique to Gp-9-carrying adults. However, colony boundaries and nestmate discrimination are poorly documented, particularly for worker-brood interactions. To delimit boundaries between field colonies, we correlated the exchange of a N-glycine tracer dissolved in a sucrose solution with social form. We also evaluated nestmate discrimination between polygyne workers and larvae in the laboratory. Counter to our expectations, polygyne colonies behaved identically to monogyne colonies, suggesting both social forms maintain strict colony boundaries. Polygyne workers also preferentially fed larval nestmates and may have selectively cannibalized non-nestmates. The levels of relatedness among workers in polygyne colonies was higher than those previously reported in North America (mean ±SE: 0.269 ± 0.037). Our study highlights the importance of combining genetic analyses with direct quantification of resource exchange to better understand the factors influencing ant invasions.

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Revisiting Ophidiomycosis (Snake Fungal Disease) After a Decade of Targeted Research

Frontiers in Veterinary Science ◽

10.3389/fvets.2021.665805 ◽

2021 ◽

Vol 8 ◽

Author(s):

Christina M. Davy ◽

Leonard Shirose ◽

Doug Campbell ◽

Rachel Dillon ◽

Christina McKenzie ◽

...

Keyword(s):

Large Scale ◽

Sublethal Effects ◽

Clinical Signs ◽

Fungal Disease ◽

Host Susceptibility ◽

Current Evidence ◽

Molecular Testing ◽

Population Declines ◽

Snake Fungal Disease ◽

Free Ranging

Emerging infectious diseases (EIDs) are typically characterized by novelty (recent detection) and by increasing incidence, distribution, and/or pathogenicity. Ophidiomycosis, also called snake fungal disease, is caused by the fungus Ophidiomyces ophidiicola (formerly “ophiodiicola”). Ophidiomycosis has been characterized as an EID and as a potential threat to populations of Nearctic snakes, sparking over a decade of targeted research. However, the severity of this threat is unclear. We reviewed the available literature to quantify incidence and effects of ophidiomycosis in Nearctic snakes, and to evaluate whether the evidence supports the ongoing characterization of ophidiomycosis as an EID. Data from Canada remain scarce, so we supplemented the literature review with surveys for O. ophidiicola in the Canadian Great Lakes region. Peer-reviewed reports of clinical signs consistent with ophidiomycosis in free-ranging, Nearctic snakes date back to at least 1998, and retrospective molecular testing of samples extend the earliest confirmed record to 1986. Diagnostic criteria varied among publications (n = 33), confounding quantitative comparisons. Ophidiomycosis was diagnosed or suspected in 36/121 captive snakes and was fatal in over half of cases (66.7%). This result may implicate captivity-related stress as a risk factor for mortality from ophidiomycosis, but could also reflect reporting bias (i.e., infections are more likely to be detected in captive snakes, and severe cases are more likely to be reported). In contrast, ophidiomycosis was diagnosed or suspected in 441/2,384 free-ranging snakes, with mortality observed in 43 (9.8 %). Ophidiomycosis was only speculatively linked to population declines, and we found no evidence that the prevalence of the pathogen or disease increased over the past decade of targeted research. Supplemental surveys and molecular (qPCR) testing in Ontario, Canada detected O. ophidiicola on 76 of 657 free-ranging snakes sampled across ~136,000 km2. The pathogen was detected at most sites despite limited and haphazard sampling. No large-scale mortality was observed. Current evidence supports previous suggestions that the pathogen is a widespread, previously unrecognized endemic, rather than a novel pathogen. Ophidiomycosis may not pose an imminent threat to Nearctic snakes, but further research should investigate potential sublethal effects of ophidiomycosis such as altered reproductive success that could impact population growth, and explore whether shifting environmental conditions may alter host susceptibility.

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Changes in landscape composition influence the decline of a threatened woodland caribou population

10.26686/wgtn.12971855 ◽

2020 ◽

Author(s):

Heiko Wittmer ◽

B McLellan ◽

R Serrouya ◽

C Apps

Keyword(s):

Large Scale ◽

Spatial Scales ◽

Apparent Competition ◽

Timber Harvesting ◽

Conservation Strategies ◽

Home Ranges ◽

Vital Rates ◽

Population Declines ◽

Woodland Caribou ◽

Habitat Alterations

Large-scale habitat loss is frequently identified with loss of biodiversity, but examples of the direct effect of habitat alterations on changes in vital rates remain rare. Quantifying and understanding the relationship between habitat composition and changes in vital rates, however, is essential for the development of effective conservation strategies. It has been suggested that the decline of woodland caribou Rangifer tarandus caribou populations in North America is precipitated by timber harvesting that creates landscapes of early seral forests. Such habitat changes have altered the predator-prey system resulting in asymmetric predation, where predators are maintained by alternative prey (i.e. apparent competition). However, a direct link between habitat condition and caribou population declines has not been documented. We estimated survival probabilities for the threatened arboreal lichen-feeding ecotype of woodland caribou in British Columbia, Canada, at two different spatial scales. At the broader scale, observed variation in adult female survival rates among 10 distinct populations (range = 0.67-0.93) was best explained by variation in the amount of early seral stands within population ranges and population density. At the finer scale, home ranges of caribou killed by predators had lower proportions of old forest and more mid-aged forest as compared with multi-annual home ranges where caribou were alive. These results are consistent with predictions from the apparent competition hypothesis and quantify direct fitness consequences for caribou following habitat alterations. We conclude that apparent competition can cause rapid population declines and even extinction where changes in species composition occur following large scale habitat change. © 2007 The Authors. Journal compilation © 2007 British Ecological Society.

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RNAi-based screens uncover a potential new role for the orphan neuropeptide receptor Moody in Drosophila female germline stem cell maintenance

PLoS ONE ◽

10.1371/journal.pone.0243756 ◽

2020 ◽

Vol 15 (12) ◽

pp. e0243756

Author(s):

Tianlu Ma ◽

Shinya Matsuoka ◽

Daniela Drummond-Barbosa

Keyword(s):

Stem Cell ◽

Egg Production ◽

Large Scale ◽

Signal To Noise Ratio ◽

Egg Laying ◽

Melatonin Receptors ◽

Germline Stem Cell ◽

Stem Cell Maintenance ◽

Female Germline ◽

Cell Maintenance

Reproduction is highly sensitive to changes in physiology and the external environment. Neuropeptides are evolutionarily conserved signaling molecules that regulate multiple physiological processes. However, the potential reproductive roles of many neuropeptide signaling pathways remain underexplored. Here, we describe the results of RNAi-based screens in Drosophila melanogaster to identify neuropeptides/neuropeptide receptors with potential roles in oogenesis. The screen read-outs were either the number of eggs laid per female per day over time or fluorescence microscopy analysis of dissected ovaries. We found that the orphan neuropeptide receptor encoded by moody (homologous to mammalian melatonin receptors) is likely required in somatic cells for normal egg production and proper germline stem cell maintenance. However, the egg laying screens had low signal-to-noise ratio and did not lead to the identification of additional candidates. Thus, although egg count assays might be useful for large-scale screens to identify oogenesis regulators that result in dramatic changes in oogenesis, more labor-intensive microscopy-based screen are better applicable for identifying new physiological regulators of oogenesis with more subtle phenotypes.

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