e-journal

Carrion mimicry in a South African orchid: flowers attract a narrow subset of the fly assemblage on animal carcasses

---

Background and Aims Although pollination of plants that attract flies by resembling their carrion brood and food sites has been reported in several angiosperm families, there has been very little work done on the level of specificity in carrion mimicry systems and the importance of plant cues in mediating such specialization. Specificity may be expected, as carrion-frequenting flies often exploit different niches, which has been interpreted as avoidance of interspecific competition. Interactions between the orchid Satyrium pumilum and a local assemblage of carrion flies were investigated, and the functional significance of floral traits, especially scent, tested. Pollination success and the incidence of pollinator-mediated self-pollination were measured and these were compared with values for orchids with sexual- and food-deceptive pollination systems.
Methods and Key Results Observations of insect visitation to animal carcasses and to flowers showed that the local assemblage of carrion flies was dominated by blow flies (Calliphoridae), house flies (Muscidae) and flesh flies (Sarcophagidae), but flowers of the orchid were pollinated exclusively by flesh flies, with a strong bias towards females that sometimes deposited live larvae on flowers. A trend towards similar partitioning of fly taxa was found in an experiment that tested the effect of large versus small carrion quantities on fly attraction. GC-MS analysis showed that floral scent is dominated by oligosulfides, 2-heptanone, p-cresol and indole, compounds that also dominate carrion scent. Flesh flies did not distinguish between floral and carrion scent in a choice experiment using olfactory cues only, which also showed that scent alone is responsible for fly attraction. Pollination success was relatively high (31.5% of flowers), but tracking of stained pollinia also revealed that a relatively high percentage (46 %) of pollen deposited on stigmas originates from the same plant.
Conclusions Satyrium pumilum selectively attracts flesh flies, probably because its relatively weak scent
resembles that of the small carrion on which these flies predominate. In this way, the plants exploit a specific subset of the insect assemblage associated with carrion. Pollination rates and levels of self-pollination were high compared with those in other deceptive orchids and it is therefore unlikely that this mimicry system evolved to promote outcrossing.
Key words: Calliphoridae, deception, floral scent, indole, oligosulfides, osmophore, outcrossing, p-cresol, Sarcophagidae, Satyrium pumilum, specialization.

---

Ketersediaan

Tidak ada salinan data

Informasi Detail

Judul Seri

Annals of Botany

No. Panggil

-

Penerbit

: Oxford University Press on behalf of the Annals of Botany Company., 2011

Deskripsi Fisik

Annals of Botany 107: 981–992, 2011

Bahasa

English

ISBN/ISSN

-

Klasifikasi

-

Tipe Isi

-

Tipe Media

-

Tipe Pembawa

-

Edisi

-

Subjek

PERTANIAN.

Info Detail Spesifik

-

Pernyataan Tanggungjawab

yuli/agus

Versi lain/terkait

Lampiran Berkas

Komentar

---

Anda harus masuk sebelum memberikan komentar