Variations on a theme, Part III

Chrysanthemum coronarium, known locally as 'Lellux', is an extremely common plant preferring to grow in 'disturbed' habitats like fields and degraded garigue. Around this time of the year it colours whole landscapes as carpets of flowers are produced to compete for pollinating insects, one of which is the beetle Oxythyrea funesta (Poda, 1761), shown below.

As can be seen in the above photograph, the colour of the flower is a bright yellow bordering on orange. This is generally common for most individuals; such a noticeable array of petals contributes to frequent pollination and therefore the yellow flowers are selected for, passing on their genes. Despite this, as in all other organisms, genetic variations that contribute to a different flower appearance do pop up from time to time. The most common of these variations is a dichroic scheme to the petals, with a discoloured (white) area appearing over part of the flower's diameter, the extent of which varies from one affected flower to another.

Most of the time, these aberrations consist of solid bands of colours, though a few may show small yellow flecks scattered over the white area.

Very rarely, the white and the bright yellow colours are not separated from each other, but mixed evenly throughout the flower, resulting in a pale yellowish flower that is far less conspicuous than usual ones.

Living snails from Malta

A number of photographs of non-marine gastropods of Malta are being hosted online in collaboration with the Associazione Malacologica Internazionale of Italy. The set focuses on the live animals, mainly as found in their typical habitats, and may be viewed here.

Variations on a theme, Part II

I have finally decided to change the appearance of the blog title by including some pictures of its namesake, which in actuality deserves a post all to itself.

The genus Muticaria Lindholm, 1925 from the peculiar family of landsnails knows as the Clausiliidae (door snails), is endemic to Sicily and Malta. Only one species exists on Malta, consisting of four main forms variously regarded in contemporary literature as varieties (Giusti et al., 1995) or actual subspecies (Nordsieck, 2007). Likewise, two main forms exist on Sicily, also regarded either as varieties of the same (Giusti et al., 1995) or as altogether different species (Beckmann, 1990).

The entity endemic to the Maltese Islands, namely Muticaria macrostoma (Cantraine, 1835) has, since the Pleistocene, diverged into local and very characteristic (though hybridizing) varieties, two of which are extremely limited in distribution. The typical forms are shown below.

I would like to thank Mr. He Jing for the excellent photographs and also for the permission to use them.

Muticaria macrostoma macrostoma (Cantraine, 1835) - Ħ'Attard

Muticaria macrostoma mamotica (Gulia, 1861) - Munxar

Muticaria macrostoma oscitans (Charpentier, 1852) - Dingli

Muticaria macrostoma scalaris (Pfeiffer, 1848) - Mistra

References:

Beckmann, K.-H., 1990. Beiträge zur Kenntnis der Landmolluskenfauna Siziliens mit der Beschreibung von Muticaria neuteboomi spec. nov. (Gastropoda: Pulmonata: Clausiliidae). Basteria, 54 (1/3): 75-85.
Giusti F., Manganelli G. & Schembri P.J., 1995. The non-marine molluscs of the Maltese Islands. Monografie Museo Regionale di Scienze Naturali, Torino, 15: 1-608.
Nordsieck, H., 2007. Worldwide door snails (Clausiliidae), recent and fossil. Hackenheim: Conchbooks, 214 pp.
Schembri, P.J. & Sultana, J. (eds.), 1989. Red Data Book for the Maltese Islands. Malta: Department of Information, pp. i-viii + 1-142 + 8 pl.

Sunset from Baħrija

Three wild Asteraceae, in bloom

Helichrysum melitense - Dwejra, 21.VI.2008


Bellis annua - Clapham Junction, 19.XII.2009

Anthemis urvilleana - Magħlaq, 26.III.2009