Species of giant cockroaches employ different strategies in the mating game

November 08, 2016

New research suggests that even in the insect world, males must adopt different strategies to win females, depending on their particular physical prowess.

It has been discovered that giant cockroaches can either be lovers or fighters depending on their species -- and have adapted their bodies accordingly to allow them to be as successful as possible in the mating game.

A study by academics at The University of Nottingham, published in the journal Scientific Reports, has shown that males from two species of giant hissing cockroaches from Madagascar may have evolved different physical characteristics based on their strategies for winning a female.

Lead author, Dr Kate Durrant in the University's School of Life Sciences, said: "These cockroaches are acting like red deer in the rut, competing for females by combat, but if they don't have the size and strength to win fights outright, they can try and sneak mates. A male cockroach seems to be adapted to be either a lover or a fighter, and what's interesting is that they do this before they become fully adult, at the final moult."

Animals that must compete for a mate can do so in various ways: some males will defend a female from rival males by force, while others will sneak past larger males and mate with females behind their backs. These two strategies, 'fighters' and 'lovers', are associated with different behaviours and characteristics. In theory, males face a trade-off in investment in weapons for fighting and investment in sperm-producing testes for mating, as there is not enough energy available to invest to be competitive in both strategies.

The Nottingham study used the latest in 3-D scanning technology based at the University's Hounsfield Facility - high-resolution X-ray CT scans -- to take precise measurements of body length, body volume and of the 'horns' carried on shields over their heads; from two different types of giant hissing cockroach: the Flat-horned cockroach, Aeluropoda insignis and the Wide-horned cockroach, Gromphadorhina oblongonota.

This was compared with the cockroaches' level of aggression when fighting rival males and the size of their testes. Larger testes mean more of an investment in mating.

They found that the Flat-horned cockroach, which is small with short horns (as its name suggests), was non-aggressive and had large testes, which indicates that it is more likely to avoid fighting by mating with females behind the backs of larger males, while the Wide-horned cockroach, which is large and heavily armoured with large horns, was highly aggressive in combat between males and was not well-endowed in terms of testes size. This indicates that the Flat-horned cockroaches were following a 'lover' strategy as a species, while Wide-horned cockroaches were following a 'fighter' strategy, and this is reflected in their anatomy and behaviour.

Patterns indicating a trade-off between lover and fighter strategies were also seen within each species - individual males that had smaller horns had comparatively larger testes to compensate, and this trade-off was stronger for the Flat-horned cockroaches.
-end-
The work was carried out in collaboration with Dr Craig Sturrock in the University's School of Biosciences, Mr Ian Skicko, now based at the University of Exeter, and Dr Sophie Mowles who is now working at Anglia Ruskin University.

University of Nottingham

Related Cockroaches Articles from Brightsurf:

Cockroach mating habits and developmental features help uncover insect evolution
A research team led by the University of Tsukuba examined the mating habits of an often-overlooked cockroach family, Nocticolidae, to provide clues about insect evolution.

Cockroaches and lizards inspire new robot developed by Ben-Gurion University researcher
'The AmphiSTAR uses a sprawling mechanism inspired by cockroaches, and it is designed to run on water at high speeds like the basilisk lizard,' says Ben-Gurion University Prof.

Salute the venerable ensign wasp, killing cockroaches for 25 million years
An Oregon State University study has identified four new species of parasitic, cockroach-killing ensign wasps that became encased in tree resin 25 million years ago and were preserved as the resin fossilized into amber.

Reducing mouse allergens may improve lung growth in asthmatic children
Lowering exposure to allergens from mice may lead to improved lung growth for children with asthma living in low-income neighborhoods, helping them avoid lung ailments and possibly live longer, according to newly published research in The Journal of Allergy and Clinical Immunology.

Turkestan cockroach selling online is a companion of the common household cockroach
The Turkestan cockroach (commonly known as the red runner roach or rusty red roach), which is popular as food for pet reptiles, has an interneuron extremely sensitive to sex pheromones emitted by American cockroaches, providing evidence that the Turkestan cockroach is phylogenetically close to the American cockroach and the smoky brown cockroach belonging to the genus Periplaneta.

Coastal organisms trapped in 99-million-year-old amber
Most amber inclusions are organisms that lived in the forest.

'Bug bombs' are ineffective killing roaches indoors
Total release foggers, commonly known as 'bug bombs,' are ineffective at removing cockroaches from indoor environments, according to a new study from North Carolina State University.

Home cleanliness, residents' tolerance predict where cockroaches take up residence
Poor home sanitation and residents' tolerance regarding German cockroaches were a good predictor of the pest's presence in their apartments, according to a Rutgers study in Paterson and Irvington, New Jersey.

Karate kicks keep cockroaches from becoming zombies, wasp chow
Far from being a weak-willed sap easily paralyzed by the emerald jewel wasp's sting to the brain -- followed by becoming a placid egg carrier and then larvae chow -- the cockroach can deliver a stunning karate kick that saves its life.

Insect toxin detected in the world's longest animal
The longest animal in the world, the bootlace worm, which can be up to 55 metres long, produces neurotoxins that can kill both crabs and cockroaches.

Read More: Cockroaches News and Cockroaches Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.