Researchers at the University of St Andrews have made a shock discovery; that restricting a normally multiply mating fish to monogamous mating does not impair their colonisation ability. Their findings show that releasing just one or two fish into the wild may be enough to trigger an aquatic invasion.

In a paper published this month in the journal BMC Ecology, researchers from the University of St Andrews tested whether forcing female guppies to be monogamous would impede their ability to establish viable populations.

The guppy (Poecilia reticulata) is a successful invasive species throughout the tropics. In the wild it employs a 'multiple mating' strategy, and resulting broods commonly contain offspring sired by up to five different fathers.

Previous studies have shown that mating with multiple partners carries a range of benefits, including increased genetic and phenotypic diversity of offspring, and inbreeding avoidance -which are potentially advantageous for a species attempting to colonise a new environment.

However, as part of this latest study, female guppies were either allowed to mate with four males, or were restricted to one partner. Pregnant females were then left to establish populations in large tanks in the laboratory. After one year, the two treatments were compared. 

Dr Amy Deacon explains:

"One of our key findings was that mating history did not predict establishment success, which was 88% in both treatments".

What's more the researchers had expected that inbreeding depression might be evident in the behaviour of fish in the monogamous treatment, which would suggest that their ability to persist once established could be limited. However, this was not the case; newborn and adult male offspring of both treatments were equally good at avoiding predators and at courting females.
These results suggest that even when denied the option of multiple mating, singly-mated female guppies can produce viable populations, at least at the founder stage.

The ability to colonise even when multiple mating is restricted may prove to be critical during introductions, where a few individuals are released into enclosed water bodies before finding their way into natural ecosystems. For example, guppies are commonly introduced into rivers or ponds as unwanted pets, or into troughs or wells for mosquito control, but later tend to spread to new habitats during floods or monsoons.

Once established in rivers and streams, aquatic invaders are notoriously difficult to eradicate.

The findings of this study reinforce the message that although seemingly harmless, releasing just one or two individuals can lead to a potentially invasive population.

The full text (open access) article can be viewed at: http://www.biomedcentral.com/1472-6785/14/18

Authored by me, this press released was edited and issued by the University of St Andrews Press Office.
Coverage in the media includes:

http://www.heraldscotland.com/news/home-news/scientists-discover-that-monogamy-does-not-curb-colonisation-by-guppies.24607524

http://phys.org/news/2014-06-invasion-monogamous-fish.html

http://cryptozoologynews.blogspot.com/2014/06/invasion-of-monogamous-fish.html

This week Professor Anne Magurran attended the Euroscience Open Forum (ESOF) in Copenhagen, accompanied by a film that was produced by Steve Smart of the School of Biology to explain what the BioTIME project is all about. The video features some great presenting skills from Dr Iain Matthews, and some rather shaky amateur camera work from me! I think it gives a nice impression of what my fieldwork in Trinidad's Northern Range is really like, and what the project is all about...

Below is a press release I have written to promote a paper that was recently published in the journal 'Ostrich':

The lakes of Kenya’s Rift Valley boast spectacular pink aggregations of lesser and greater flamingos. Over the last 20 years these populations have suffered a series of unexplained mass mortality events, during which hundreds of thousands of birds die over a period of just a few months.

Not only is this a distressing sight to witness, it is also a serious concern for conservationists.

The Rift Valley lakes represent the largest of four populations of this species worldwide – consisting of around 1.5-2.5 million birds. Because only a handful of salt lakes support this huge population, these mysterious die-offs have the potential to threaten the global health of the species.

Suggested causes for the die-offs range from infectious diseases such as avian tuberculosis and avian cholera, to poisoning by cyanobacterial toxins, insecticides or heavy metals. This variety of potential causes means that over the years studies have been undertaken by researchers from many different disciplines, each using different approaches. The result has been samples that cannot easily be compared with each other, and no consensus on the underlying cause. There is a real need for the standardisation of sample-taking and examination if we are to understand the causes of mortality in these birds.

In a paper published this month in the journal ‘Ostrich’, Professor John Cooper, Dr Amy Deacon and Dr Thomas Nyariki present tried and tested protocols for the post-mortem examination of flamingos, so that we will be better prepared in the event of future die-offs. The strength of these easy-to-follow protocols lies in their flexibility, which allows them to be adjusted according to the available labour and number of dead birds.

 When there are many birds and/or few staff, the ‘super-fast track’ form ensures that the most essential data and vital samples will be prioritised; when there are fewer birds and/or more people, instructions for a comprehensive examination can be followed.

Professor Cooper has confidence that the new protocols will prove vital to conservation efforts:

“We believe that collecting standardised samples and measurements will be the key to finally finding the cause of these highly concerning events, and ultimately being able to   prevent future die-offs and protect this globally important population.”

As well as being important primary consumers in the soda lake ecosystem, the promise of the once-in-a-lifetime experience of seeing these stunning pink birds in their millions draws large numbers of international tourists to the Rift Valley. With 15,000 visitors each year to Lake Bogoria alone, the long-term protection of this species is of great economic, as well as ecological, importance to the region.

Cooper, J. E., Deacon, A. E., & Nyariki, T. (2014). Post-mortem examination and sampling of African flamingos (Phoenicopteridae) under field conditions. Ostrich, 85(1), 75-83.