Sunday, 25 May 2008

The Pollen and Nectar-Feeding Katydids

The Pollen and Nectar-Feeding Katydids

The Pollen and Nectar-feeding katydids (Tettigoniidae; Zaprochilinae) are represented by four genera comprising some 17 species. The entire group is endemic to Australia and all species are nocturnal. They appear to be related to the Australian Stick Katydids (subfamily Phasmodinae), a group known only from heath habitats in coastal south and west Western Australia. These are katydids that are easily recognisable and often very common.

Both groups have specialised mouthparts suited for dealing with a range of flowers. The Stick Katydids eat both pollen and the flowers themselves, whereas, the Pollen and Nectar Feeding Katydids seem to deal only with pollen and nectar, leaving the remaining floral bits untouched. It is the latter group that we will deal with here.

Fig. 1. Male Anthophiloptera dryas Rentz and Clyne. Note protruding mouthparts.

The four genera comprising the zaprochilines are distributed widely across Australia; however, no Pollen and Nectar Feeding species have been recorded from the Northern Territory. The most recent review of the group was by myself, Rentz (1993). One species. The Balsam Beast, Anthophiloptera dryas Rentz and Clyne, was the only species known at the time from far north Queensland. It has an extraordinary range for a katydid, extending  from Cairns south to Batemans Bay, NSW. It occurs in coastal rainforests and was first discovered by Densey Clyne in her garden when she lived in Turramurra, a suburb of Sydney. She documented its incredible life history and recorded it in a number of her books, for example see Clyne (1982). It was a pleasant discovery to find it in our rainforest patch in Kuranda, more than 2000 km from our coastal forest at our home in Bawley Point, NSW where we also found it.

Fig. 2. Male A. dryas. Note the shape of the wings and the angle at which they are to the body.

A. dryas is the largest known member of the Pollen and Nectar-feeding Katydid subfamily with females measuring as much as 35 mm in body length, with the tegmina added it almost doubles that length. These insects are the most “prognathous” of the group with the head lengthened to facilitate feeding deep into flowers. They feed on a wide range of pollen and nectar. Eggs are laid in cracks in the bark of trees, presumably near a reliable food source. Nymphs have a peculiar resting posture that has not been observed in any other katydid groups (see below). As they grow, they change their shape and become more brown and cryptic, resembling twigs and stems. Females always have 2 spots on the top of the abdomen. The adults sit in a characteristic position during the day, motionless with less outstretched with their ventral surface tightly in contact with the substrate and the forelegs and antennae outstretched and parallel in front. The tegmina are held at 30O from the body surface as in Zaprochilus and Windbalea, which are noted below.

The Green Flower-feeding Katydids, Windbalea spp., are beautiful katydids known from only a few localities along the south coast of southwestern Western Australia. At first glance they resemble the green katydids of the genus Polichne but the resemblance to Anthophiloptera species is apparent when closely examined. These katydids eat both pollen and nectar as well as other floral parts. They are locally abundant and very important relics in a disappearing habitat that is uniquely Australia.

Fig. 2. Windbalea viride Rentz, a Green Flower-feeding katydid from the Esperance region of Western Australia.

The Small Flower-feeding Katydids were largely unknown because they are small, the males short-winged, females wingless and they occur as adults during the winter and early spring. One genus, Kawanaphilus, is known comprising some 11 species. They are active at night even when temperatures are in single figures. By the time the warmer temperatures return, they are largely gone. They are present in heath habitats in the southern part of Australia in heath habitats on both sides of the continent. The ease with which they can be obtained and kept in the laboratory has lead them to be important laboratory animals at the University of Western Australia where resident zoologists, visitors and students have studied them intensively. They have been important players in studies of sexual selection in insects involving mate preferences, intermale competition and their controlling factors. See Gwynne & Simmons (1990), for example. One species has appeared on the cover of Nature (1990, vol. 346, number 6280). Eleven species have been described to date. The hairy body of Kawanaphila species suggests that they may be involved with pollination as tiny pollen grains adhere to the hairs and can easily be moved from flower to flower.

Fig. 3. A Small Flower-feeding Katydid, Kawanaphila iyouta Rentz from Western Australia. This is a female. Note the short ovipositor.


The Pollen and Nectar-feeding Katydids of the genus Zaprochilus are very characteristic and widespread. Four species are known. Three are long-winged and capable of flight, the other is a short-winged species from a single locality in an arid portion of Western Australia north of Perth. The long-winded species have the wings held at a distinctive angle with the body. In addition, the outer wings (tegmina) seem to be rolled or cylindrical. This and the mottled greyish colour serves in twig mimicry.


Fig. 4. A male Zaprochilus australis. Note characteristic resting position and the "rolled" subcylindrical wings.

As an aside that might be of interest, Zaprochilus australis (Brullé) is one of the earliest described species of Australian Orthoptera. The first specimen was collected on an expedition authorised by Napoleon Bonaparte that comprised two vessels, one, Le Géographe the other Le Naturaliste. The former ship was captained by Capt. Nicholas Baudin, the purported collector of the type of the species on Kangaroo Island, South Australia in 1802 or, perhaps, in 1803 when another ship, the Casuarina returned there. This species is the most widespread of the genus and occurs across the southern end of the continent and seems quite abundant at times.

One species of Zaprochilus has been found in Kuranda. Z. mongabarra Rentz, is known from northern New South Wales, the Brisbane area of Queensland and they hundreds of kilometres to the north around the Mt Windsor Tableland and the Cairns vicinity. It does not seem to be as common as Z. australis and seems to be more arboreal than that species. Males can be heard stridulating with a Mini Bat Detector after dark from high in rainforest trees.

Fig. 5. Adult male Zaprochilus mongabarra Rentz. Note tip of abdomen. The structures are important identification features.


Fig. 6. Scanning electron micrograph of the tip of the abdomen of a male Z. mongabarra.


Fig. 7. Scanning electron micrograph of the stridulatory file of a male of Z. mongabarra. This structure is located on the underside of the left wing (tegmen). Each species has a characteristic file- in length, shape and number of teeth. When this is struck against a raised vein on the opposite tegmen, a sound is produced. The physiology of the species and the features of the tegmen along with the file produces a sound that is species distinctive. Males sing to attract females.

References

Clyne, D. 1982. Wildlife in the Suburbs. Oxford University Press, Pp-1-201.

Gwynne, D. T., Simmons, 1990. Experimental reversal of courtship roles in an insect. Nature, 346: 172-174.

Rentz, D. C. F. 1993. A Monograph of the Tettigoniidae of Australia. Volume 2. The Austrosaginae, Zaprochilinae and Phasmodinae. Pp 1-386. CSIRO Information Services, East Melbourne, Victoria Australia.

1 comment:

Denis Wilson said...

Hi Dave.
Well now I feel fully informed on the Nectar and Pollen feeding Katydids.
Thanks so much for your help in identifying mine!
Cheers
Denis