Navigation Links
Captive breeding for thousands of years has impaired olfactory functions in silkmoths

This news release is available in German.

Silk: A natural product for 5000 years

The silkmoth Bombyx mori, originally native to China, was domesticated about 5000 years ago. Its larvae, silkworms, enclose themselves in a cocoon when they enter the pupa phase. They spin their cocoon from one single silk thread, which is several hundred meters long. For silk production, the cocoon − together with the pupa inside − is boiled and the silk filament is then unraveled. Special breeding moths are kept for silk farming. After mating female moths lay several hundred eggs from which the new silkworms hatch.

In the 1950s Bombyx mori became a model organism in modern olfactory research. The sex pheromone bombykol, released by female silkmoths, was the first insect pheromone to be characterized chemically. Bombyx mori males' are highly sensitive to even a few molecules of the female attractant, and the sensilla on their antennae are easily accessible for electrodes. This made them an ideal model system for electrophysiological measurements to analyze their olfactory functions. As early as 1956, olfactory receptor responses, so-called electroantennograms, were recorded on Bombyx mori.

Still responsive to pheromones, but not to environmental odors

Scientists from the Department of Evolutionary Neuroethology at the Max Planck Institute for Chemical Ecology and their collaborators from Japan have found that Bombyx mori is now considerably impaired in its olfactory functions due to 5000 years of captive breeding. The moth's perception of environmental odors, which may lead it to its exclusive host plant, the mulberry tree, has been significantly reduced. This was demonstrated when their responses to odor stimulation were compared to those of the closely related wild species Bombyx mandarina. The scientists recorded electroantennograms of individuals of both species that were stimulated with different scents from leaves or flowers.

Morphological analysis revealed that the number of sensilla on the antennae of Bombyx mori females is considerably reduced compared to the abundant sensilla of Bombyx mandarina. In addition, the researchers measured different activity patterns in the brain of the domesticated and the wild silkmoths by using calcium imaging techniques. These patterns were highly variable among individuals of domesticated silkmoths but were largely constant in their wild ancestor group as well as in four other insect species.

Compared to wild moths, domesticated silkmoths seem to have less ability to smell environmental odors with their antennae and to locate host plants due to several millennia in captivity. As oviposition substrate is provided by humans, this ability has become redundant. In the wild, however, selecting an adequate oviposition site is crucial for the survival of the offspring, and thus helps preserve the species.

On the other side, perception of the female-produced attractant bombykol in Bombyx mori males is unabated, although it is not necessary anymore to find the females, as they are presented to the males by the breeders. Probably because bombykol not only attracts males but also triggers mating behavior in the males, it has remained indispensable for reproductive success.

Domestication effects are localized on the sex chromosome

Unlike in mammals, the female ovule determines the sex of the offspring in moths and butterflies. The distinction is made, analogous to the XY chromosomes, between W and Z chromosomes. Males have ZZ, females WZ chromosomes. Because both species, B. mori and B. mandarina, can still be crossbred, the scientists bred hybrids and used them for further olfactory experiments. "The modification of the Bombyx mori olfactory system, namely the reduced perception of environmental odors, is very likely caused by mutations on the female W chromosome. Differences in the signal processing in the moth's brain, however, are not located on the sex chromosomes," Sonja Bisch-Knaden, first author of the study, summarizes the results of the hybrid experiments.

Combining classical methods of electroantennogram recordings with advanced imaging techniques to analyze responses in the olfactory centre of the silk moth brains opens new perspectives in olfactory research: from molecule to behavior. [AO/JWK]


Contact: Dr. Silke Sachse
Max Planck Institute for Chemical Ecology

Related medicine news :

1. Power Grid System Market (Captive Generation, Wind Power) in Subsea Worth $2,365.1 Million by 2018 - New Report by MarketsandMarkets
2. Leading National Law Firm Anderson Kill & Olick Concludes NRRA Not Intended to Apply to Captive Insurance Companies
3. Reveals How Project CAP and Insurance Agoragate will Take Away Market Share from the Captive Insurance Carriers and give it back to the Independents
4. Urban Hospitals May Act as Breeding Ground for MRSA
5. Little Rock Car Dealership Raises Thousands For Breast Cancer Research
6. Project could save the eyesight of thousands
7. Thousands Expected to Attend CCAR’s 14th Annual "Recovery Walks!" Friday, September 27 to Support Recovery from Alcohol and Other Drug Addiction
8. Virtual Doctors Save Consumers Thousands in Medical Expenses With New Subjective Health Quiz
9. Thousands to shape £8 million age-friendly design projects
10. Cloud-Based EHRs with Integrated Billing Solutions May Save Thousands of Independent Physicians from Acquisition, Reveals Black Book RCM study
11. Thousands Expected to Attend CCAR’s 14th Annual “Recovery Walks!” Friday, September 27 to Support Recovery From Alcohol and Other Drug Addiction
Post Your Comments:
Related Image:
Captive breeding for thousands of years has impaired olfactory functions in silkmoths
(Date:11/27/2015)... (PRWEB) , ... November 27, 2015 , ... ... affecting the health care in America. As people age, more care is needed, ... costs are rising, and medical professionals are being overworked. The forgotten part of ...
(Date:11/27/2015)... CA (PRWEB) , ... November 27, 2015 , ... Lizzie’s ... , The company is offering customers 10% off of their purchase of lice treatment ... treatment at full price. According to a company spokesperson. “Finding lice is a sure ...
(Date:11/27/2015)... ... November 27, 2015 , ... Consistent with the Radiology ... Building Better Radiology Marketing Programs meeting will showcase some of the best ... at Caesars Palace in Las Vegas with a pre-conference session on a collaborative ...
(Date:11/27/2015)... ... November 27, 2015 , ... Keeping in mind ... mental health and wellness consultation, has collaborated with a leading web-based marketplace for ... gap experienced by parents and bring advice from parenting experts within their reach. ...
(Date:11/27/2015)... ... , ... Avid collector, Andrew Hawley from Vintage Rock Posters, announces his search ... one of Joplin's most famous and beautiful concert posters. The concert was held on ... Arbor. The According to Hawley, "It is hard to believe that Joplin's stardom was ...
Breaking Medicine News(10 mins):
(Date:11/25/2015)... , Nov. 25, 2015 ... the addition of the "Global Brain ... their offering. --> ) ... "Global Brain Monitoring Devices Market 2015-2019" ... Research and Markets ( ) has ...
(Date:11/25/2015)... THOUSAND OAKS, Calif. , Nov. 25, 2015 /PRNewswire/ ... of a Biologics License Application (BLA) with ... Administration (FDA) for ABP 501, a biosimilar candidate to ... the first adalimumab biosimilar application submitted to the FDA ... biosimilar pathway. Sean E. Harper , M.D., ...
(Date:11/25/2015)... WOODBURY, N.Y. , Nov. 25, 2015  Linden ... access and optimizing treatment outcomes for patients suffering from ... its request for a Temporary Restraining Order (TRO) enjoining ... between the two companies. --> ... aggressively pursuing all of its legal options. ...
Breaking Medicine Technology: