Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cricket’s finicky mating behavior boosts biodiversity

07.02.2005


Speedy speciation curbs courtship options, says Nature article

Biologists at Lehigh University and the University of Maryland have identified a cricket living in Hawaii’s forests as the world’s fastest-evolving invertebrate. Finicky mating behavior appears to be the driving force behind the speedy speciation of the Laupala cricket, the scientists wrote in the Jan. 27 issue of Nature magazine.

Females in the Laupala genus detect tiny differences in the pulse rates of male courtship songs, which differ from one Laupala species to the next. They refuse to mate with males of other species, thus promoting the formation of new species.



The scientists say their findings shed light on the role of individual choices in the evolution of species and the growth of biodiversity. "Animals with nervous systems and brains have preferences and can make choices," says Tamra Mendelson, an evolutionary biologist at Lehigh. "Changes in these preferences and choices appear to drive speciation. "That raises the question: Can something seemingly so individual as a choice have macro-evolutionary consequences in terms of increasing biodiversity? If so, this affects how life on the planet looks. The more species you have, the more complex the ecology is going to be."

In down-to-earth terms:

"What turns a female cricket on? Why does she prefer one pulse rate over another? Whatever the reason, it’s very important that she exercise this preference in order to keep the species distinct."

Mendelson spent three and one-half years studying the Laupala cricket with Kerry Shaw, an evolutionary biologist at the University of Maryland.

The thumbnail-sized Laupala spawns new species at the rate of 4.17 every 1 million years, or more than 10 times faster than the average speciation rate for invertebrates. This rapid evolution is contributing to an "explosion" of new cricket species, especially on Hawaii, the largest and youngest island in the Hawaiian archipelago, say the two scientists. Some 38 different species of the cricket now inhabit the island chain.

Among all animals, say Mendelson and Shaw, only the African cichlid fish spawns new species more quickly. While early biologists based their estimates of speciation rates on morphological, or structural characteristics, Mendelson says, scientists today are more likely to use genetic data to come up with estimates.

Closely related species of Laupala have no clear morphological differences, Mendelson says. They are similar in appearance, they have similar diets, and they live in similar habitats. Members of closely related species possess no physiological differences that would prevent them from interbreeding. But closely related species are distinguished by subtle differences in the pulse rates of male crickets’ simple courtship songs, a secondary sexual trait that plays a large role in mate attraction.

Among all species of Laupala, pulse rates of male courtship songs range from .5 to 4.2 pulses per second. Female crickets can detect these differences, says Mendelson, and they tend to hop towards the pulse rate of their own species and to reject songs sung at a different tempo. The Laupala mating ritual lasts up to eight hours and consists of eight to 15 transfers of spermatophores between male and female, says Mendelson. The final spermatophore, or capsule, to be transferred contains the actual sperm cells that impregnate the female. As a species begins to split into two separate species, says Mendelson, "the songs appear to be the first characteristic that changes."

During the early part of the speciation process, says Mendelson, crickets of the two emerging lines interbreed. After a point, however, members of the two distinct species no longer mate with each other. This discovery led Mendelson to name one of her graduate-school papers after the pop song "Will You Still Love Me Tomorrow?" The Nature article was given the more conservative title of "Rapid Speciation in an Arthropod."

"Over time," says Mendelson, "lineages - species that have split - cease to recognize each other as mates. Although the ancestors recognized each other as mates, the descendants no longer do because of evolutionary change. In the case of Laupala, members of the two species are physiologically capable of mating. But they appear to lose the desire to interbreed before they lose the capacity to interbreed."

Mendelson and Shaw used a technique called amplified fragment-length polymorphisms to establish the evolutionary tree, or phylogeny, of the Laupala. They based their estimates of the cricket’s rate of speciation on the Laupala’s phylogeny and on the age of the islands in the Hawaiian archipelago. The youngest island, Hawaii, was formed less than 500,000 years ago.

Kurt Pfitzer | EurekAlert!
Further information:
http://www.lehigh.edu

More articles from Life Sciences:

nachricht Kidney tumor: Genetic trigger discovered
18.06.2018 | Julius-Maximilians-Universität Würzburg

nachricht New type of photosynthesis discovered
18.06.2018 | Imperial College London

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

Im Focus: Photoexcited graphene puzzle solved

A boost for graphene-based light detectors

Light detection and control lies at the heart of many modern device applications, such as smartphone cameras. Using graphene as a light-sensitive material for...

Im Focus: Water is not the same as water

Water molecules exist in two different forms with almost identical physical properties. For the first time, researchers have succeeded in separating the two forms to show that they can exhibit different chemical reactivities. These results were reported by researchers from the University of Basel and their colleagues in Hamburg in the scientific journal Nature Communications.

From a chemical perspective, water is a molecule in which a single oxygen atom is linked to two hydrogen atoms. It is less well known that water exists in two...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Novel method for investigating pore geometry in rocks

18.06.2018 | Earth Sciences

Diamond watch components

18.06.2018 | Process Engineering

New type of photosynthesis discovered

18.06.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>