Friday, 30 May 2014

The Last Throes of Summer

Here in the tropics we approach the Dry Season with cooler temperatures, lower humidity, less rain and fewer insects- It's almost winter in the tropics.

Harbingers of the end of the wet season are some of the following orthopteroid insects.

Meet the Mundurra Fierce Predatory Katydid, Hexacentrus mundurra Rentz.
 Males hang upside down and stridulate from dusk from low perches in open areas of grassland and mixed vegetation. The incessant song continues until late in the evening when tmeratures drop. The sound is loud and travels for a great distance. It can easily be heard from a moving car.
 This species is a true predator and it seems to specialise in subduing other katydids.
Females look quite different from the males. The wings are just used for short flights or gliding, whereas, the males wings (tegmina) are modified for sound production. Males can also take short flights when necessary. However, the escape technique is to drop deep into the vegetation and remain still until the danger passes.
The Giant Rainforest Mantis (at least 60 mm in length), Hierodula majuscula (Tindale), Mantidae; Mantinae seems to show up at the lights for only a few weeks at the end of the season. I have never seen nymphs around in the garden so I assume it drops by on its nocturnal excursions. The spines on the forelegs can deliver a painful prick if this species is not handled carefully.
The most surpsising drop-in is the Migratory Locust, Locusta migratoria Linnaeus, Acrididae; Acridinae; Oedpiodini. This large locust is thought not to fly at night and but I have found it at light in Kuranda sporadically over the years but only during May. I have recorded it in May 2005, 2009, 2010 and 2014. On our last trip to the Daintree, it was very common and large numbers of individuals would take flight when disturbed during the day. However, after dark many were found sedentary in grass and none were attracted to our lights. This species is a grass feeder.

The only plague of recorded for this species in Australia was 1974-76 during favourable years. However, overseas this species is a major pest of rice, corn, sorghum and related plants.

No comments: