Navigation Links
Flies may reveal evolutionary step to live birth
Date:11/25/2008

A species of fruit fly from the Seychelles Islands often lays larvae instead of eggs, UC San Diego biologists have discovered. Clues to how animals switch from laying eggs to live birth may be found in the well-studied species' ecology and genes.

The fly is one of a dozen species of Drosophila to have recently had their genomes sequenced, information that should provide abundant opportunities for identifying genetic changes that cause females of this species, and not others, to retain their fertilized eggs until they are ready to hatch.

The result was so surprising that the scientists initially thought it was a mistake.

"The student who was timing things came a said 'wow, these eggs in this species really develop quickly' sometimes in less than an hour. That's not possible," said Therese Markow, a professor of biology who led the project. "When I went and actually looked at them I saw that they were depositing something that was very advanced, that hatched into a larva right away. In several cases they were hatching as they were being laid."

Even those Seychelles fly eggs that emerged unhatched were at an advanced state of development, the team reports in forthcoming issue of the Journal of Evolutionary Biology. Most larvae emerged within two hours compared to an average of nearly 23 hours for the other 10 species in the study.

The Seychelles flies also laid larger eggs--nearly double the average volumes found for the other species--and their ovaries have fewer threadlike structures called ovarioles in which insect eggs mature before fertilization.

Live birth could result from changes to the male reproductive strategy as well. Proteins found in the semen of the well-known lab fruit fly, Drosophila melanogaster, stimulate egg laying in the female. A modification of these signals could be responsible for the switch.

"That signaling mechanism between the male and the female has changed. We don't know the basis for it, but we ought to be looking," Markow said. "It's very interesting. It tells you who's really going to be able control reproduction."

Early hatching offers advantages, the authors say. Mobile larvae can burrow into the ground to avoid becoming inadvertent hosts to the eggs of parasitic insects or a predator's meal. But harboring offspring for a longer period of time costs the female.

The opportunity to take that risk may come with specialization. The Seychelles flies feed only on the fruit of the morinda tree, a tropical plant that produces year round, but is toxic to other fruit flies, giving this single species exclusive access.

One other fly in the study, Drosophila yakuba, also occasionally laid larvae instead of eggs, and their eggs also hatched fairly quickly, most in under 14 hours. It too specializes in a particular fruit, that of the Pandanus tree.


'/>"/>

Contact: Susan Brown
sdbrown@ucsd.edu
858-246-1061
University of California - San Diego
Source:Eurekalert  

Related biology news :

1. Researchers find new taste in fruit flies: carbonated water
2. Flies can turn off their immune response
3. Tiny pest-eating insect fights fruit flies
4. The precise role of seminal proteins in sustaining post-mating responses in fruit flies
5. Smell-wars between butterflies and ants
6. CSHL scientists identify a mechanism that helps fruit flies lock-in memories
7. Fruit flies show how salmonella escapes immune defenses
8. Monarch butterflies help explain why parasites harm hosts
9. Courtship pattern shaped by emergence of a new gene in fruit flies
10. Brain tweak lets sleep-deprived flies stay sharp
11. Old before their time? Aging in flies under natural vs. laboratory conditions
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Flies may reveal evolutionary step to live birth
(Date:2/2/2016)... Va. , Feb. 2, 2016   ... award from the U.S. Army Research Office and ... the range and sensitivity of the company,s ... Past Accounting Mission and, more generally, defense-related DNA ... DNA phenotyping capabilities (predicting appearance and ancestry from ...
(Date:1/28/2016)... -- Synaptics (NASDAQ: SYNA ), a leading developer of human ... December 31, 2015. --> --> ... 2 percent compared to the comparable quarter last year to $470.5 ... $35.0 million, or $0.93 per diluted share. ... quarter of fiscal 2016 grew 9 percent over the prior year ...
(Date:1/22/2016)... 22, 2016 ... the "Global Biometrics Market in Retail ... --> http://www.researchandmarkets.com/research/p74whf/global_biometrics ) has ... Biometrics Market in Retail Sector 2016-2020" ... Research and Markets ( http://www.researchandmarkets.com/research/p74whf/global_biometrics ) ...
Breaking Biology News(10 mins):
(Date:2/3/2016)... Feb. 3, 2016 Ascendis Pharma A/S (Nasdaq: ... applies its innovative TransCon technology to address significant unmet ... upcoming investor conference.Event:2016 Leerink Partners Global Healthcare Conference Location: ... Wednesday, February 10, 2016 Time:  , 11:55am EST ... --> An audio webcast of this event ...
(Date:2/3/2016)... 3, 2016 New Jersey Health Foundation (NJHF) ... million for researchers in New Jersey ... that demonstrates exciting potential.   James ... the New Jersey Health Foundation Research Grant Program ... educational institutions— Princeton University, Rutgers University, Rowan University ...
(Date:2/3/2016)... ... February 03, 2016 , ... ProMIS ... potential targets (epitopes) specific to misfolded, propagating strains of Amyloid beta involved in ... antibody therapeutics for Alzheimer’s. , Following on from the first misfolded Amyloid beta ...
(Date:2/3/2016)... ... February 03, 2016 , ... ... report which summarizes and analyzes nearly 750 unique supply chain notifications and ... analysis service. , Supply chain risk management practitioners subscribe to the EventWatch ...
Breaking Biology Technology: