Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Invasive honeysuckle opens door for new hybrid insect species

28.07.2005


The animal family tree may not be filled just with forks, but may also contain knots: hybrid species with two different ancestors rather than one, according to a team of Penn State researchers.



"We are looking for the origin of species," says Dr. Dietmar Schwarz, post-doctoral researcher in entomology. "In animals, people envision the formation of a new species by a split of one ancestral species to two derived species or a branching of one species from another."

However, according to Schwarz, another way to get a new species is for two species to hybridize – mate with each other – forming a new species lineage while the parental species persists.


"It is thought that over 50 percent of plants came into being this way, but that this mechanism played hardly any role in animals," says Schwarz. "Hybridization was seen as an accident resulting in sterile offspring like mules, but not as the beginning of a new species."

In the plant world, many plants create hybrid species by doubling the number of chromosomes in the parent for the offspring generation, but some hybrids, like the sunflower species, do contain the same number of chromosomes as the parents. For a handful of animal species – some fish – genetic information suggests hybridization as the most likely form of origin, but only a little is known about the actual mechanism.

"The real problem for the formation of a new species is ecological compatibility," says Schwarz. "Is there some ecological niche that is not already in use?"

Schwarz; Bruce A. McPheron, professor of entomology and associate dean for research and director of Pennsylvania Agricultural Experiment Station; and Benjamin M. Matta and Nicole Shakir-Botteri, Penn State undergraduate biology majors who have since graduated, present their findings on a hybrid tephritid fruit fly – the Lonicera fly, a member of the Rhagoletis pomonella species complex -- and its host resource, the non-native brushy honeysuckle, in the July 28 issue of the journal Nature.

Exotic brushy honeysuckle may have come to North America as early as 1750, but probably became established in 1880 when the U.S. Department of Agriculture introduced it as an ornamental and wildlife plant. The plant now grows wild throughout the Northeastern United States. The introduction of this plant, however, provided an unused resource that could initiate a host shift for the flies. Rather than gradually adapt to a new host plant, the flies hybridized.

Tephritid fruit flies are specialized fruit parasites. Each species of fly uses only one berry-bearing plant as its host where adult flies mate on the bushes and lay their eggs in the berries in the summer. The larvae hatch and grow in the fruit, destroying the berry. When mature, the larvae crawl out of the berry, drop to the ground and pupate, waiting through the winter to emerge as adults. This type of host-dependent lifestyle is very common. More than 50 percent of all animal species, many of them tiny plant eaters and parasites, are believed to be host specialists like Rhagoletis tephritid flies.

Blueberry tephritid flies mate on blueberry bushes and snowberry tephritid flies mate on snowberry bushes. This helps to avoid matings with a partner from the wrong host plant and keeps the two different parent species separate. Matings between species occur on occasion, but the hybrid offspring are short lived because they are believed to do much worse on either blueberry or snowberry than its parents.

Schwarz thinks that the introduction of invasive, brushy honeysuckle caused a breakdown of this isolation and created a fly that completes its reproductive cycle in the brushy honeysuckle berry.

"As far as we can tell, we think the new species is already reproductively isolated," says Schwarz. "They seem to be in a niche on the brushy honeysuckle where the parent species cannot compete."

Reproductive isolation – not interbreeding with either of the parent species -- is one requirement for a species.

The researchers note that it is very difficult to detect new species like the brushy honeysuckle fly. The two parent species look like identical twins and can only be distinguished by their different genetic makeup. It is also difficult to determine that the fly is a true hybrid species and not a pre-existing, but undiscovered, species that was formed without hybridization. The researchers can estimate what the first generation of a cross between blueberry and snowberry flies looks like genetically, but by the time the species is established, there are no longer any offspring of the original cross mating around to investigate.

So, Schwarz used a standard approach and looked at genetic markers in the brushy honeysuckle fly. He compared those markers with genes from other tephritid flies. He found that the blueberry and snowberry flies, because of their specific genetic makeups, were the only possible combination of parents for the brushy honeysuckle fly.

"This kind of comparison can only be done because so much is known about this type of fly," says Schwarz. "But there might be a lot more animal hybrid species than previously thought if researchers take a closer look."

Human activity has resulted in the rapid mixing of plants and animals that had no previous contact with each other. According to the researchers, such man-made disturbances could create many more situations in which new hybrid species could form.

The National Science Foundation supported this research.

A’ndrea Elyse Messer | EurekAlert!
Further information:
http://www.psu.edu

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

DGIST develops 20 times faster biosensor

24.04.2017 | Physics and Astronomy

Nanoimprinted hyperlens array: Paving the way for practical super-resolution imaging

24.04.2017 | Materials Sciences

Atomic-level motion may drive bacteria's ability to evade immune system defenses

24.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>