New paper in Journal of European Orchids

04.08.2022

Studies on Pollination Biology of the Orchid Genus Ophrys of Mallorca.

Paulus HF. 2022
J. Eur. Orch. 54 (1-2): 501-562.

Abstract

Pollination biology of the orchid genus Ophrys has been studied on the island of Mallorca (Spain) during several visits in the years 1997, 1998 and 2009 from the beginning of February to the middle of April. Observations and experimental choice tests in the field have revealed several new Ophrys-pollinator relationships. These results and floral morphological investigations yield the following systematic conclusions:

1. The pollinator of the widely distributed Ophrys speculum is confirmed to be the wasp Dasyscolia ciliata (Scoliidae), unusual common in the north of Mallorca.

2. The long-horned bee, Eucera oraniensis, is confirmed to be the pollinator of Ophrys bombyliflora.

3. The pollinator of Ophrys tenthredinifera s.str. is in Mallorca as in the whole Mediterranean area of this species the long-horned bee Eucera nigrilabris. No pollinator could be found fort he recently discovered large flowered Ophrys spectabilis. Because of the unusual flower size, I supposed Bombus terrestris. But in field tests this bumblebee showed no interest. The pollinator is the large long-horned bee Eucera rufa (=berlandi) (Benito Ayuso 2017). This new species could be an endemic of Mallorca and is not identical with Ophrys ficalhoana from the Spanish mainland.

4. The pollinator of Ophrys balearica (from the O. bertoloniiformis species-group) was first discovered in 1997 and is the megachilid bee, Megachile (Chalicocoma) sicula. This distinct pollinator argues for specific status of this plant taxon. The bee, however, is the same species found as pollinator of the near related Ophrys explanata from Sicily. The whole species-group was re-evaluated by using the morphometric data published by Gölz & Reinhard (1975, 1979).

5. The Ophrys fusca s.str. group in Mallorca consists of at least four different species. A large-flowered species, Ophrys forestieri Lojacono (synonyms are lupercalis Devillers & Devillers-Terschuren 1994, and O. decembris S. Moingeon & J.-M. Moingeon 2011) blooming from December until early March (maximum flowering in January). It is pollinated by Andrena nigroaenea. Another O. fusca-type pollinated by Andrena flavipes blooms from the middle of February until April (maximum flowering period in March). The labellum is smaller and mostly yellow margined. Because of the striking similarity between O. caesiella from N-Africa I classified this type in earlier time as O. bilunulata subsp. caesiella (Paulus 2014). But after the revalidation of the old name subfusca by Lowe (2011), it has to be new classified as Ophrys bilunulata subsp. subfusca (Paulus 2020). The third fusca type starts blooming in end of March/early April and has very small flowers. Its pollinator is the very small Andrena fabrella. As flower morphology and phenology are clearly distinct from all other fusca types, it was described as Ophrys fabrella Paulus & Ayasse ex Delforge 2004. This tiny species is also distributed on Ibiza and Formentera. From middle of April on starts a further fusca form with large lips: Ophrys arnoldii. Its pollinator are males of the second generation of Andrena nigroaenea.

6. The pollinator of the so-called Ophrys dyris in Mallorca is the endemic Anthophora balearica, a near relative of Anthophora atroalba. This latter bee is pollinator of the southern Spanish O. dyris. Males of Anthophora balearica show no preferences in choice tests between “normal” O. dyris and presumed hybrids between O. dyris and O. fusca s.lat. (O. X brigittae), which have a small longitudinal notch at the base of the labellum. Such intermediate forms are quite common in Mallorca among normal ones. It is thought that these plants are influenced by forestieri/arnoldii introgression long time ago or represent a type of atavism.

7. Based on distributional patterns, the biogeography of the orchid flora is discussed. Elements belonging to relicts of an old distribution type (Thyrrenean type) in the central Mediterranean area appear noteworthy. It is exemplified by the distribution pattern of Serapias nurrica.

Anthophora balearica on Ophrys dyris (Mallorca)

© Hannes Paulus