Weevil or beetle?

Let me begin by admitting that my title question is misleading: weevils are different from most beetles in a very recognisable way but they are in fact still beetles, a family within the order Coleoptera which includes longicorns, elephant beetles and all the others.

Wikipedia informs us that Curculionidae, “the “true” weevils (or “snout beetles”) … are one of the largest animal families, with 6,800 genera and 83,000 species described worldwide.” It’s not surprising, then, that, “with so many species, a spirited debate exists about the relationships between subfamilies and genera,” (Wikipedia’s polite way of saying that the experts are still arguing).

CSIRO’s invaluable site says that weevils are, “Highly variable in form, but usually moderately to strongly convex, robust, heavily sclerotised and often clothed with scales or bristles. Head always more or less produced [i.e. extended] in front of eyes to form a rostrum, which is usually much longer than broad; antennae always geniculate [elbowed] with long scape and more or less compact club.” Many of those features can be seen in my photos of an individual I found in my garden recently:

weevil
Weevil on a frangipani branch

Continue reading “Weevil or beetle?”

Eat, Lay, Love – insects’ search for fulfilment

Life is simpler for insects than for us. Like us, they have to eat and reproduce. Unlike us, they don’t seem to want to achieve anything more than that, unless you count avoiding predators as an ambition.

These photos were taken in my garden at different times and don’t have much else in common except that their subjects are doing something more than merely resting.

Longicorn beetles (Cerambycidae) are usually identified by their exceptionally long, curved antennae. Their larvae are wood-borers and adults usually eat bark, although this one (probably a Double-coned Longicorn, Zygocera plumifera) seems to have no aversion to lichen.

longicorn beetle
Longicorn beetle eating lichen on a frangipani branch

When I started taking an interest in insects I quickly found that flies (Diptera) were far more numerous and more varied than I had guessed; better-looking and less harmful to us, too, if not positively beneficial. Many of them mimic colourful wasps, while many adults are nectar-feeders and some larvae are predators of plant pests.

The Soldier fly, Hermetia illucens, looks and behaves like a rather sleepy black wasp. Adults don’t feed at all, so they can neither bite us nor transmit diseases. The larvae are scavengers and decomposers, which makes the compost bin a particularly suitable place for the female to lay her eggs.

black fly
Soldier fly laying eggs under the lip of a compost bin lid

These lovers are also wasp-mimicking flies, Plecia amplipennis. They don’t really have a common name in Australia but are known overseas as ‘Love Bugs‘ for their habit of staying mated, like these two, for extremely long periods and even flying mated. When not engaged in this way, adults feed on nectar and pollen to keep up their strength.

black flies
Plecia mating on a bottlebrush twig

Insects enjoying the nectar

long skinny wasp
Gasteruptid wasp

Bug hunters love flowers, not just for their own sake but for the bugs they attract. This set of photos shows most of the insects I saw in just ten or fifteen minutes on one profusely flowering shrub in Anderson Park, beginning with the wasps.

blue-black wasp on white flowers
Blue flower wasp, Scoliidae

This wasp is possibly a Blue Flower Wasp, Scolia soror, and certainly a close relation if not that particular species. There was another similar one feeding on the same shrub, distinguishable by a bright yellow patch on the back of its head; it may have been Scolia verticalis (see them both here, on Graeme Cocks’ site).

Scoliidae is just one family of wasps, the Flower wasps. Gasteruptidae (top pic) is another (BugGuide calls them “Carrot Wasps” and you can see why, but I don’t think they have a genuinely common name), and there are many more including Polistinae, the Paper wasps. This index page on Graeme’s site shows them with their nearest relations, the bees and ants.

small green bee on white flowers
Green native bee

This small native bee (Colletidae) is similar to one which appeared on my earlier all-on-one-plant post. The beetle below is not just similar – it is definitely the same species:

brown beetle on white flowers
Brown Flower Beetle, Glycyphana stolata
small fawn butterfly on flowers
Lycaenid butterfly

The odd angle of this shot was forced on me by my uncooperative subject but does allow me to point out a neat bit of mimicry: the eye-spots and tails on the lower part of the wings are a surprisingly good imitation of the butterfly’s head and antennae (there’s an even more striking example here, on a related butterfly). I’m sure this is not a coincidence, since tricking predators into attacking non-vital parts is great for survival.

blue dragonfly perching on twig
Palemouth Shorttail dragonfly, Brachydiplax denticauda

All the other insects here were attracted to the flowers. This dragonfly just wanted to perch for a while and found a suitable bare twig. He happens to be the first carnivore (insectivore?) on the page and he may well be looking out for prey amongst the smaller bugs attracted to the flowers. As I said in the beginning, bug hunters love flowers.