When the ant Cephalotes atratus is infected with a parasitic nematode, its normally black abdomen turns red, resembling the many red berries in the tropical forest canopy. According to researchers, this is a strategy concocted by nematodes to entice birds to eat the normally unpalatable ant and spread the parasite in their droppings. (Steve Yanoviak/University of Arkansas)

Ant parasite turns host into ripe red berry, biologists discover

By Robert Sanders, Media Relations | 16 January 2008

Video In this video, an infected ant appears to interact normally with its coworkers, though its berry-like red abdomen makes it stick out from the rest. (Steve Yanoviak and BBC)

BERKELEY –A newly discovered parasite so dramatically transforms its host, an ant, that the ant comes to resemble a juicy red berry, ripe for picking, according to a report accepted for publication in The American Naturalist. This is the first example of fruit mimicry caused by a parasite, the co-authors say.

Presumably, the dramatic change in appearance and behavior tricks birds into eating infected ants - parasites and all - so that the bird can spread the parasite in its feces. The fruit-eating birds' droppings, which are mostly seeds and insect parts, are gathered by other ants who then feed and unwittingly infect their young.

نتايج يك تحقيق جديد نشان مي‌دهد كه نسل دايناسورها احتمالا در اثر گزيدگي با نيش حشرات حامل بيماري طي يك دوره طولاني از روي كره زمين منقرض شده است.

به گزارش سرويس «علمي» خبرگزاري دانشجويان ايران (ايسنا)، براساس اين فرضيه، افزايش و تكامل حشرات به ويژه گونه‌هايي كه انتقال دهنده‌ بيماري‌ها بوده‌اند، نقش مهمي در ريشه كني نسل دايناسورهاي غول پيكر از روي زمين داشته است.

دانشمندان مي‌گويند: ما در بزاق يك حشره نيش دار انگلی را شناسايي كرده‌ايم كه مي‌تواند باعث بروز بيماري ليشمانيا شود كه هنوز هم بيماري خطرناكي محسوب مي‌شود.

اين بيماري مي‌تواند هم خزندگان و هم انسان‌ها را مبتلا كند.

در يك حشره ديگر نيز ميكروارگانيسم‌هايي را شناسايي كرديم كه عامل بروز نوعي خاص از مالاريا هستند كه پرندگان و مارمولك‌هاي امروزي را آلوده مي‌كنند.

آنها مي‌افزايند: از سوي ديگر در فضولات دايناسورها ميكروب‌هايي را يافت كرديم كه عامل بروز اسهال خوني و ساير بيماري‌ها و اختلالات شكمي هستند.

دانشمندان دانشگاه ايالتي اورگون در ادامه اظهار مي‌كنند: اين واقعيت‌ها دانشمندان را به سوي اين بحث كشاند كه حشرات مي توانسته‌اند زمينه‌اي مؤثر و آرام براي كاهش جمعيت دايناسورها و در نهايت انقراض آنها فراهم كنند.

به علاوه حشرات مي‌توانند باعث بيماري و تخريب گياهان و سبزيجاتي شوند كه منبع تغذيه‌يي دايناسورها بوده‌اند.

Insect Attack May Have

Finished Off Dinosaurs

ScienceDaily (Jan. 4, 2008) — Asteroid impacts or massive volcanic flows might have occurred around the time dinosaurs became extinct, but a new arguemet is that the mightiest creatures the world has ever known may have been brought down by a tiny, much less dramatic force -- biting, disease-carrying insects.

Tick found in Burmese amber.
(Credit: Image courtesy of Oregon State University)

An important contributor to the demise of the dinosaurs, experts say, could have been the rise and evolution of insects, especially the slow-but-overwhelming threat posed by new disease carriers. And the evidence for this emerging threat has been captured in almost lifelike-detail -- many types of insects preserved in amber that date to the time when dinosaurs disappeared.