Navigation Links
For crickets, parasitic flies can stop the music

Love hurts ?really bad, for some unlucky crickets, anyway.

Male crickets draw not only females with their songs but also parasitic flies. The uninvited guests then deposit larvae that burrow into their amorous hosts, grow for about a week and then tear their way out in "Alien" fashion, killing the cricket as they emerge.

Now, University of Florida zoologists have found that the danger posed by the flies has apparently affected when crickets sing. In experiments with Southeastern U.S. field crickets, known scientifically as Gryllus rubens, they discovered that considerably fewer male crickets sing in the autumn when the parasitic flies are abundant. They also found that female crickets are reluctant to approach singing males in the fall, perhaps unknowingly avoiding becoming the target of the flies themselves.

The findings, reported in a pair of recent papers in the journals Ethology and Animal Behavior, are of interest because they shed light on the interplay between the powerful evolutionary forces of sexual selection and natural selection, said UF zoology professor Jane Brockmann.

On the one hand, singing and finding mates increases a male’s reproductive success; on the other, it also carries high potential costs, Brockmann said. "The interesting question is how exactly do these conflicting pressures play out in evolution""

Scientists have known for some time that parasitic flies, known scientifically as Ormia ochracea, deposit larvae on, or near, singing crickets. The larvae burrow into the insects, then feed on nonessential organs within the cricket while they grow. After they emerge from the dying cricket, they pupate and metamorphose into mature flies.

Brockmann and co-author Manuel Vélez, a former UF student who earned his doctorate in 2004, hypothesized that the presence of flies would affect how male crickets sing and how females respond. Examining wild crickets native to North Florida, they devised two sets of experiments to test this hypothesis.

In experiments involving male crickets, they gauged differences in male singing in part by capturing males, placing them in containers in the field, then recording them during spring and fall. They also surveyed free singing males in a pasture during the two seasons.

In North Florida, the parasitic flies are present only in fall, never in spring. The researchers?findings seemed to agree with this schedule. More of the males sang in the spring than in fall, with 75 percent of the captured males, for example, singing in spring and 43 percent in fall.

To test how female crickets respond to the flies, the scientists captured and placed spring and fall females in cages, then played recordings of male songs and observed their reactions. Paralleling the result with the males, more of the spring females approached the speaker quickly and more closely than the fall females.

"The spring females are extremely eager. The minute they hear a male singing, they race over to the speaker," Brockmann said. "The fall females are much more hesitant. They take longer and seem reluctant to approach the speaker."

Brockmann said although scientists have examined similar phenomena in other species such as guppies, it is rare to observe obvious female courtship behaviors. Female crickets, by contrast, actually mount the males, so it is easy to know what they are choosing. Also, she said, the complete absence of parasitic flies in spring allows the researchers to examine the role of flies as a selective pressure on male singing and female mate choice behavior.

That said, not all of the findings were clear-cut. Although fewer males sing in the fall, for example, the ones that sing do so far longer, placing themselves at even greater jeopardy of being parasitized by the flies. Brockmann said this may reflect the presence of many more females in the fall, enabling male singers to mate man y more times.

Also, many male crickets never sing, apparently finding mates by simply walking around until they encounter females. That raises the question, why sing in the first place" Brockmann said the answer may have to do with the subtle interplay between the density of flies, the density of crickets and the presence of other predators that prey on walking crickets.

Walkers may do better when mates are abundant and other predators are few, while singers may have better luck when mates are relatively rare and fly populations are low. "It might be quite a dynamic thing," she said. "Some years, there’s selection against one, some years there’s selection against the other."

Source:University of Florida

Related biology news :

1. Yale researchers identify molecule for detecting parasitic infection in humans
2. Worm hormone discovery may aid fight against parasitic disease
3. Researchers add crucial information on how the bodys T cells react to parasitic diseases
4. Common parasitic infection leads to increased risk for HIV infection
5. Master gene controls healing of skin in fruit flies and mammals
6. Remote control flies? Fly behavior controlled by laser light
7. UI researcher studies deafness in fruit flies, humans
8. How monarch butterflies are wired for navigation
9. Gap-climbing fruit flies reveal components of goal-driven behaviors
10. Expanding forests darken the outlook for butterflies, study shows
11. Hormones and growth: The control of body size and developmental growth rate in fruit flies

Post Your Comments:

(Date:11/9/2015)... 2015 ... "Global Law Enforcement Biometrics Market 2015-2019" ... ) has announced the addition ... Market 2015-2019" report to their offering. ... ) has announced the addition of ...
(Date:11/4/2015)... --> --> ... Transparency Market Research "Home Security Solutions Market - Global Industry ... 2022", the global home security solutions market is expected to reach ... market is estimated to expand at a CAGR of ... Rising security needs among customers at homes, the emergence ...
(Date:10/29/2015)... 29, 2015   MedNet Solutions , an innovative ... of clinical research, is pleased to announce that it ... (MHTA) as one of only three finalists for a ... Small and Growing" category. The Tekne Awards honor ... superior technology innovation and leadership. iMedNet™ ...
Breaking Biology News(10 mins):
(Date:11/30/2015)...  AbbVie, is introducing Good Morning Hypothyroidism ... routine for managing the life-long condition of hypothyroidism. When ... way the body absorbs it so resources encouraging patients ... are important. The goal of the new website ... hypothyroidism by establishing a daily routine, spirit of connection, ...
(Date:11/28/2015)... (PRWEB) , ... November 28, 2015 , ... • Jeon ... eco-friendly avian, porcine and rodent control solutions , ... and cinnamon oil, works across all sensory modalities including visual, smell, taste and touch, ...
(Date:11/26/2015)... 26, 2015 --> ... in imaging technologies, announced today that it has received a ... the Horizon 2020 European Union Framework Programme for Research and ... trial in breast cancer. , --> ... --> --> The study aims to ...
(Date:11/25/2015)... HOLLISTON, Mass. , Nov. 25, 2015 /PRNewswire/ ... ), a biotechnology company developing bioengineered organ implants for ... will present at the LD Micro "Main Event" ... p.m. PT. The presentation will be webcast live and ... will also be available at the conference for one-on-one ...
Breaking Biology Technology: