The guest speaker for our October meeting was Otto Mueller and his topic was ‘Glimpses of something small’. Otto is an avid student of the insect world and likes to use his microscope to study aspects or organisms that are not clear to the naked eye. His talks are always interesting and informative, providing a different view of the natural world to that we typically encounter. This talk proved to be no different.

The first subtopic was galls or scale insects. His first photo was of a large gall. Photos of small lumps on a leaf followed this and Otto asked the question ‘gall or scale insect?’ The lumps were an armoured scale (<1mm) that provided pyramidal protection for larvae and can be found in different shapes. Otto then showed a photo of adults that had hatched in a jar overnight. More photos of galls followed, including a red gall that stood out from the brown branch. Otto opened up one of the red galls and photos of it showed a jelly-like substance inside and a larva forming within the jelly. He showed us more photos of red and green galls on leaves and told us that the galls prevent the development of the leaves. Another red gall that Otto opened presented a view of an almost fully-developed, tiny winged insect—a fly or wasp (probably the latter) that was around 5mm long. Otto the showed a photo of a tiny wasp (<5mm long), referred to as a gall wasp, whose telltale features were the antennae and wing venation. Otto finished this portion of the presentation with a photo of a woody gall, around 6cm long. He explained that this was the result of an insect making holes in the stem and laying eggs into the hole. The gall results from the plant attempting to heal the area damaged by the holes. As the larvae feed on the stem or branch, the plant continues its efforts to heal the damaged area and the large gall is the end result.

Part two of the presentation was titled ‘Insect-consuming Plants’. Otto proceeded to demonstrate how the Sundews (Drosera sp.) consume insects caught in the sticky leaves. A series of photos showed a typical Drosera stem; Drosera leaves changing shape; and a partially dissolved insect. These were followed by a close up photo of a leaf and then another close up of a leaf with a small grasshopper caught by the sticky droplets showing all tentacles in the leaf bending towards the insect (a process that continues until the leaf is wrapped around the insect).

The final part of the presentation outlined how a plant protected its buds and unopened flowers. Otto was interested to know why the tips of buds of one of the Tetragonia sp. were stuck together. He explained that the plant was protecting its undeveloped leaves. He examined the bud under the microscope—where it had the appearance of the tip of a pair of tweezers. As time passed, the bud opened exposing a flower, showing that the mechanism was to protect the developing flowers from predation by insects before they had a chance to open and be pollinated.

Colin Prickett