Month: August 2013

My name is Adam Reddon, and I study the behavioural biology of social living. I have a particular fascination with both aggression and sociality and I endeavor to better understand these behaviours through the integration of functional, developmental and mechanistic perspectives. My Ph.D. work focused on social decision making in the contexts of grouping behaviour and resource contests in a highly social cichlid fish. I am finishing my PhD at McMaster University this month and will soon be moving to Montreal to take up a postdoctoral fellowship at McGill University in Simon Reader’s research group. During my postdoctoral work I plan to examine the effects of maternal experience on the social behaviour and physiology of her offspring in guppies.

 

Email: reddonar@mcmaster.ca

Website: http://www.science.mcmaster.ca/psychology/people/262-adam-r-reddon.html

Google Scholar: http://scholar.google.ca/citations?user=MM1KKXcAAAAJ&hl=en

Twitter: @adamreddon

Fight Club

Among those that study how animals interact with one and other, there are two basic groups: those who are mostly interested in what the boys have to say to the girls (or vice versa), and those who are mostly interested in how animals settle disputes among members of their own sex. The former group is certainly larger than the later, as evidenced by the fact that this Animal Behaviour Society Meeting had around 60 or 70 talks on sexual selection broadly defined, including a couple of plenaries, while there was but one session on agonism, or fighting as it is better known. Furthermore, the lone agonism section happened to fall into the last slot of the last day, a time when many conference attendees are often running short on attention span or have wandered off to explore whatever lovely locale in which the conference is set (Boulder, CO has this in spades). So, you can imagine my trepidation when I discovered that my talk was in the last slot of this last session, on the last day, in a topic that warranted only the lone session out of around 80 or so. I envisioned speaking in front of the other speakers from the session, 100 empty chairs and perhaps a janitor catching a nap in the back row. Much to my delight, the agonism session was very dynamic and well attended! This, I think can only be credited to the exceptional talks that joined my own in rounding out this session. All five of the other talks very interesting and engaging. I learned a great deal and very much enjoyed this session. Below are some brief descriptions of each of the 6 talks:

Sara Decker, University of Wyoming – Sara’s talk was about dominance hierarchies in a very interesting species of bird, the long-tailed mannequin. Long-tailed mannequin males form groups and work together to attract females. Only the dominant most male gets to breed though, and he has a second in command that is next in line for breeder status. Sara found that if both of these two top ranked males disappeared at the same time, the group descended into chaos and in-fighting, which apparently long-tailed mannequin females do not like, as they stop coming around until the chaos dies down and the hierarchy becomes stable again.

Bruce Lyon, University of California Santa Cruz – Bruce talked about dominance interactions in gold-crowned sparrows. Gold-crowned sparrows, like many birds, use badges of status to settle disputes without needing to escalate to costly violence. Males of this sparrow have a bright yellow patch of feathers atop their head. Birds with a bigger patch are dominant over those with a smaller patch. In a staged interaction between two birds, you can change who wins by using paint to give one bird an artificially larger patch. Interestingly, Bruce presented data showing that this manipulation doesn’t work if the birds are from the same flock and already know each other. Presumably, they remember the other bird, know what that bird is really like and hence are not fooled by the new dye-job.

Chad Johnson, Arizona State University – The rapid expansion of Phoenix, Arizona from small desert settlement to one the largest, most bustling metropolises in North America has posed many challenges for the local flora and fauna. One animal that seems to be doing ok with the new neighbors is the western black widow spider. This poisonous character is doing so well it has become a major urban pest. Interestingly, Chad presents data showing that although western black widows are super abundant in the city, the city-dwellers are actually less healthy than their desert counterparts that have to eke out a living under much tougher circumstances. Chad found that this unexpected difference seems to owe to the fact that the city spiders eat mostly a particular cricket species, which is low on phosphorus, a vital nutrient for western black widows. Basically, city spiders are gorging themselves on junk food, which lets them reproduce quickly, but spiders from more natural areas are getting a more varied and complete diet, resulting in better overall health.

Russell Ligon, Arizona State University – Russell studies aggressive interactions in veiled chameleons, which can change their body colour rapidly, and may do so to communicate with one another. Russell found that the brightness of a chameleon’s body predicted its likelihood of escalating to physical fighting, while the chameleon with the darker head was signaling submissiveness and was unlikely to win the fight.

Vikram Iyengar, Villanova University – Vikram presented data on sexually selected trait divergence in a pair of related damselflies. These species may live together in the same areas, or in different areas. When they co-occur, one species tends to have smaller spots on its wings than it does when the other species isn’t around. Previous research has shown that these wing spots are attractive to females. Vikram’s study showed that the wing spots also draw the ire of males of the other species, causing them to attack more often. Vikram’s data suggests that males in areas of overlap have been selected for smaller wing spots because although it makes them a bit less sexy, it also saves them some costly beatings.

Adam Reddon, McMaster University – Last up to bat was my talk. I told the audience about a recent study comparing the decisions during fights between two closely related species of cichlid fish, one of them highly social (frequent star of this blog, Neolamprologus pulcher) and the other (Telmatochromis temporalis) much less so. I predicted that because the social species may have more information about their opponents before a fight because they have interacted with them before, and because the social species may have a greater overlap in interests with their opponents, the social species would have less costly fights. I also predicted that the social species may find a way to end a conflict that allowed them to stay in the same area and continue to interact with their opponent after the fight, whereas the less social species may just run away and go somewhere else. My results confirmed both of these predictions, suggesting that changes in the way animals fight may be tightly linked to their social system, how they live with and get along with other members of their species. The morning of my talk, I found out that the paper this data was drawn from was accepted for publication in the journal Behaviour. I considered this a good omen, and sure enough, my talk went great. I was happy with my performance and got lots of positive feedback afterwards. Best of all, lots of smart people hung in there to the end and listened to me speak. It was a great way to end a great meeting.

Cody Dey is an evolutionary ecologist who studies social behaviour in birds and fish. He is primarily interested in signalling, mating systems, whiskey and beards.

As you have probably heard in Isaac’s previous incarnations of “Weird Bio Sh*t”, animals do some crazy stuff. Some of the craziest traits and behaviours we observe in the natural world are those that are involved in reproduction. For example, males of many species of birds have extremely elaborate ornamentation and behaviours (check out the wild dances and songs in this video) that are used to attract mates. The evolution of traits used only for reproduction is extremely interesting to behavioural biologists because these traits are the product of strong selection (if you don’t mate your genes are quickly removed from the gene pool), however sexually selected traits often decrease the survival of their bearer (e.g. the peacock’s long tail makes it more prone to predation because it is bulky and conspicuous).

Sexual selection was first thought up by Charles Darwin himself. Typically, we think of sexual selection occurring when females choose a mate from a pool of different males. In order to stand out, males have evolved special attractive traits that are used to broadcast how sexy they are to females. Alternatively, sexual selection can also occur when males have to fight to gain access to females. In this case, males often evolve complex weapons that are used to duke it out (think moose antlers or fiddler crab craws).

This year at ABS, there was a great deal of discussion of how, why and when sexual selection occurs in animals and what consequences it has on the natural world. Robin Tinghitella told us how female choice for mates can be affected by mate availability and age. Apparently, female sticklebacks (a species of fish) are less choosy when males are harder to come by. Also, female sticklebacks get less choosy as they age. The ability of females to adjust how choosy they are allows female sticklebacks to balance the goal of gaining a high quality mate with the costs of not getting a mate at all.

We also heard how sexual selection can lead to speciation (the process of creating new species!). Biologists first thought that sexual selection might be involved in speciation when they looked at closely related animals and noticed that the primary difference between many species is in male ornaments. Since these ornaments are usually produced by sexual selection, it seems likely that sexual selection has some role in creating new species. Dr. Rebecca Safran showed that in different populations of barn swallows, females prefer either males with longer tails or males with darker breast plumage. Since females have different preferences in these different populations, it is possible that the different populations will diverge into different species (as males gain longer tails in one population, and darker breasts in the other population).

Finally, we heard how male white-crowned sparrows use the colour of their crown as a signal of dominance. Males with more white on their crown are dominant over those with less white on their crown. These ‘status signals’ determine which males get the best territories and therefore get to mate. However, status signals are thought to be advantageous to all males because they can be used to resolve conflict without resorting to a full on fight, which can be extremely costly because the combatants could get injured. Status signals are common in males of many species, but behavioural biologists are still struggling to explain how these signalling systems remain honest. It is still somewhat unclear why subordinate individuals don’t grow large status signals in order to appear more dominant, but there are some emerging ideas of why this kind of ‘cheating’ may not be beneficial.

Sexual selection is still a field of intense interest for biologists even though Darwin first formalized the idea in 1871. It is likely the study of sexual selection will continue indefinitely because it produces some of the most interesting behaviours we observe in the natural world. Additionally, sexual selection is a dynamic process that is being affected by our changing environment and the tools available for the study of sexual selection are evolving at an astronomical rate. Indeed, it is truly an exciting time to study the sex lives of animals.

Photo of a Social Spider nest – from http://www.texasento.net

There have been a number of really cool talks at this years ABS conference. I’ll briefly describe a  few that have been particularly interesting to me:

Duck penis morphology:

You may have heard in the news recently about Dr. Patricia Brennan and her research on duck penis morphology. While I could spend a whole post justifying why she should receive NSF funding for this work, she explained it extremely well here. Dr. Brennans talk at ABS focused on plasticity (changes in an organisms characteristics in response to environment) in duck penis morphology. Some species of ducks have high rates of forced extra-pair copulations (rape), and these species typically have larger and more complex penis structures to more efficiently inseminate females. Dr. Brennan predicted that social context would influence the growth of penises in these species. She found that in the species with more forced extra-pair copulations there was increased plasticity – males grew larger penises to deal with increased competition for females when multiple males were housed together with females.

Personality in Founding Individuals:

In light of HIREC (Human Induced Rapid Environmental Change), some species are entering new territories. Dr. Jonathan Pruitt suggests that the personalities of these founding individuals is important for understanding the pattern and success of these invasions. Personalities, or behavioral syndromes, are repeatable patterns of individual behavior across context. Variation in personality has been found in an immense number of species. In social spiders, Dr. Pruitt has found variation in how bold and aggressive these individuals are. When an individual forms a new colony, they deal with other spider species that parasitize their immense nests. Aggressive individuals kill these parasites off, while more docile spiders tolerate the other spiders. While colonies founded by docile spiders are initially more successful, in the long run they are far more likely to collapse than those founded by aggressive spiders.

Agricultural Amoebas:

Humans aren’t the only species that tries to privatize resources. Dr. Joan Strassmann described a species of bacteria-eating amoebas in which some colonies farm several species of bacterium. Some are kept as a food source; while another, which they cannot eat is farmed for its chemical product which they use as a weapon against non-farming competitor colonies.

Look forward to a post in the next few days from Adam Reddon on the Agonism (fighting) session which occurred this afternoon!