Helophorus, Fabricius, 1775

Fikáček, Martin, Skuhrovec, Jiří, Šípek, Petr & Fikáček, for abstracts see, 2011, Abstracts of the Immature Beetles Meeting 2011, Acta Entomologica Musei Nationalis Pragae 51 (2), pp. 731-756 : 733-735

Rearing Helophorus : egg cocoons & larvae

Robert B. ANGUS

Department of Entomology, The Natural History Museum, Cromwell Road, London SW7 5BD, UK; e-mail: r.angus @rhul.ac.uk

Adult Helophorus may be kept in small aquaria (sandwich boxes) with a bank of sand at one end, and water to a depth of about 1 cm. They are fed with algae (typically Spirogyra ), moribund grass or occasionally freeze-dried peas. Decomposing vegetation should be removed.

Egg cocoons are usually placed in the bank, but occasionally among the vegetation in the water. The consist of an egg bag about 3–5 mm long, topped by a silk mast of three main forms: 1. Erect, leaf-like; 2. Tubular; 3. Thin ribbon-like, corresponding to the leaf-like masts of type 1 or the back of the tubes of type 2; 4. Long tubular ribbon-like masts corresponding to the entire tubes of type 2. It is suggested that the form of the mast may be important in supplying oxygen to developing eggs, erect leaves and ribbons floating upwards because of trapped air will act as physical gills if cocoons are flooded, while the slightly deeper burial of cocoons with tubular masts could delay desiccation of the cocoon in hot dry conditions. One species, H. asturiensis Kuwert , has been found to make two distinct types of cocoon (types 2 and 4).

Egg cocoons are harvested daily and kept on damp filter paper in Petri dishes.

Larvae are normally fed on Tubifex worms (available from aquarists’ suppliers). In the wild it is possible to improvise – in West Siberia I used chopped up Gammarus lacustris , abundant locally. Larvae are given their first feed in the dish with the cocoon, but after one day are transferred to individual pill boxes, on four sheets of damp filter paper. The filter paper must be fully damp, but without any loose water. Food is supplied daily and uneaten food from the previous day removed. Hygiene is essential, and soiled filter papers are changed as necessary.

There are normally three larval instars (but only two in H. kirgisicus Knisch and H. kervillei d’Orchymont ), and at temperatures of about 23° C the larvae are ready to pupate in about two weeks. Larvae pupate in banks of damp sand in the pill boxes. Pupation takes about two weeks.

I kept larvae as cleared mounted preparations in Canada balsam on microscope slides. I have found that such preparations keep their colour.

Some aspects of larval morphology are discussed.

Primary larvae of some Ripiphorinae : their phoresy and dispersal ( Coleoptera : Ripiphoridae )

Jan BATELKA

Nad vodovodem 16, CZ-100 00 Praha 10, Czech Republic; e-mail: [e-mail]

Dispersal abilities of Ripiphorinae have never been studied in the past. Although all members of the subfamily are well known for their phoretic triungulinid primary larvae similar to those in some Meloidae (Coleoptera) or in Strepsiptera , their capability to colonize distant localities has been investigated only recently (BATELKA 2011, BATELKA & STRAKA 2011). The main features and factors allowing members of two Ripiphorinae genera ( Macrosiagon Hentz, 1830 and Ripiphorus Bosc, 1791 ) to reach a distant and even very isolated habitats (like oceanic volcanic islands) by the long-range dispersal are shown and discussed. Results will help with future evaluation of biogeography of these two genera.

Primary larvae (so called ‘triungulinids’) of Macrosiagon and Ripiphorus show remarkable adaptations for phoresy. Besides their streamlined body shape similar to other phoretic larvae, their pretarsal segments are modified into leaf-shaped pulvilli (or inflatable lobes) which probably help them to crawl in the blossoms to reach their host bees or wasps when they are approaching, their mandibles are sharp and pointed to be able to penetrate soft cuticle or wings of their vectors during the transport, and finally their terminal abdominal segment is modified into retractile sucker capable of adhesion to smooth substrates (TOMLIN & MILLER 1989).

Several genera and species of flowering plants visited by adults of certain species of Macrosiagon and Ripiphorus in the Arabian Peninsula and Africa were identified. Importance of these plants for phoresy of ripiphorine free-living primary larvae is discussed. The term ‘transfer plants’ has been introduced to highlight their significance in the life cycle of the associated ripiphorine species. Ovipositing in the inflorescences of these transfer plants in some species was found out to be the reason of the multiple triungulinid load on their hymenopteran host species (i.e., more than one primary larva on a single vector). Phoretic adaptations of primary larvae, widely distributed transfer plant taxa (either on the tribal or generic level) and the multiple triungulinid load mechanism seem to be responsible for a wide distribution of some ripiphorine species and successful colonization of remote places such as arid areas, high mountain ranges or oceanic volcanic islands by the members of this subfamily.

Morphology of the phoretic primary larval instar of Ripiphorus caboverdianus Batelka & Straka, 2011 has been described, that of R. arabiafelix Batelka, 2009 from Yemen will be described in the forthcoming paper (BATELKA in prep.). Original sampling method to obtain R. arabiafelix primary larvae in the field was developed. Larvae were collected by using cut-off PET bottles half-filled by water with several drops of detergent. Inflorescences of the transfer plant were immersed in the liquid for a few seconds. Positive samples with larvae sunken to the bottom of the bottle are detectable by 20× magnifying glass directly in the field. Several tens of larvae may be obtained in a few minutes.

Five long-range dispersal events in the subfamily Ripiphorinae in the Afrotropical Region were documented. Ripiphorus caboverdianus from the Cape Verde islands represents the first record of the family Ripiphoridae from the volcanic islands west of Africa and the first record of the genus on an isolated volcanic archipelago worldwide. Macrosiagon benschi insularum Schilder, 1923 from the volcanic Comoros belongs to an endemic Malagasy species-group with three Madagascan taxa. Finally, three widely distributed Afrotropical Macrosiagon species common to Africa and Madagascar were identified (BATELKA 2011, BATELKA & STRAKA 2011).

BATELKA J. 2011: Contribution to the synonymies, distributions, and bionomics of the Old World species of Macrosiagon ( Coleoptera : Ripiphoridae ). Acta Entomologica Musei Nationalis Pragae 51: XX–XX

BATELKA J. (in prep.): Transfer plants of some Ripiphorinae in Africa and Arabia with remarks on the primary larva of Ripiphorus arabiafelix ( Coleoptera : Ripiphoridae ).

BATELKA J. & STRAKA J. 2011: Ripiphorus caboverdianus sp. nov. – the first ripiphorid record from the Macaronesian volcanic islands ( Coleoptera : Ripiphoridae : Ripiphorinae ). Zootaxa 2792: 51–62.

TOMLIN A. D. & MILLER J. J. 1989: Physical and behavioral factors governing the pattern and distribution of Rhipiphoridae (Coleoptera) attached to wings of Halictidae (Hymenoptera) . Annals of the Entomological Society of America 82: 785–791.