How small ‘guys’ can get the ‘gals’ just as their bigger counterparts

June 25th, 2009 - 2:00 pm ICT by ANI  

Washington, June 25 (ANI): In the world of yellow dung flies, it’s the small guys who get the girl, but only if they are hanging out on apple pomace instead of cow dung, reveals a new study.

While the large, brawny males almost always have an upper hand in getting a mate, but this is the first time that alternative male reproductive strategies have been observed in this species.

Syracuse University (N.Y.) undergraduate students found that small male dung flies, which are traditionally unsuccessful at finding and keeping mates on dung pats, successfully mated with females feeding on composting apple pomace.

In fact, large males were generally absent from the pomace mounds.

“This is a new chapter in the story of yellow dung flies. No one has carefully studied this species off the dung. Small male dung flies can’t compete with their larger counterparts on the dung, so in this case, they developed a different tactic to successfully pass their genes to the next generation,” said Scott Pitnick, professor of biology in SU’s College of Arts and Sciences.

The students were tasked with designing a study around the size and mating success of yellow dung flies.

“After we made our initial field observations for the class assignment, we could tell from our professors’ reactions that our discovery was a piece of important information in the field. The course was designed to teach us how to be biologists; as such, we made a unique observation that ultimately resulted in a publication,” said Stephen Maheux ‘09, a biology major who graduated in May.

The researchers believed that yellow dung flies mated almost exclusively on manure and females were drawn to the dung only when they are ready to mate.

However, Pitnick said that not much is known about the feeding habits of females when they are not at the dung pats.

On the other hand, males were thought to hang out almost exclusively around the manure, awaiting the arrival of the females.

Competition on the dung among males is fierce and can result in injury or death to smaller males as well as females caught up in the struggle.

However, on Toad Hollow Farms in Nedrow, N.Y., the students noticed large numbers of females feeding on apple pomace in a field adjacent to the cow pasture where they were observing flies on dung pats.

Surprisingly, the females were frequently mating on the pomace, and with males that were significantly smaller in size than those found in the cow pasture.

Furthermore, none of the sexually aggressive behaviours normally observed on the dung pats occurred on the pomace.

Apple pomace is the pressed pulp that remains after juicing.

The students’ initial observations suggested that the availability of the pomace seemed to provide male dung flies with alternative mating opportunities.

The study is published in the latest issue of Proceedings of The Royal Society. (ANI)

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