22nd March, 2019

Summary & Follow-up

The Special Topic for our March workshop was
Insect Orders: how to tell a bug from a beetle, a wasp from a fly

1. Mystery Insects

People arrived with a range of insects (and other organisms) they were seeking to identify.

Live animals including: caterpillars, very feisty bull ants, diving beetles, backswimmers, a tiny dragonfly larva, a centipede, and even a slater.

Various photos, including: a katydid, two colourful beetles, and a colony of wasps.

And a couple of recently deceased insects: a small yellow moth and a brown butterfly.

Andrew was rather creative in getting this close-up shot of a moth. He put it under the micro-eye (microscope) and then took a shot of the TV screen with his phone. A novel macro-photography method – it works well!

2. Insect Diversity

First, the taxonomic context … insects are a class within the phylum Arthropoda

Before we talk more about insect orders, what is an order anyway?

Species are grouped based on their evolutionary relationships. The smallest group is genus. A genus contains a group of very closely related species. Widening the circle, a group of related genera (plural for genus) are grouped together into a family. And wider still is the level order: a group of families that all share a common ancestor.

When it comes to insects, there are real advantages to being able to recognise different orders.

• If you know the order, you already know quite a lot about the insect. For example, if you know it’s a beetle (Coleoptera) and not a bug (Hemiptera), you know something about the kind of larvae it has. Beetle larvae are grubs - they look nothing like adult beetles. Bug larvae are called nymphs, and they’re really just mini-adults.

• If you know the order, you know what kinds of books or lists of photos to search next if you want to identify it further. For example, if you know it’s a beetle, the next thing to do is reach for a book on beetles, or search a list of local beetle species.

For some insect orders, the number of species is huge.

The table above shows why identification to genus or even family can be considered a good outcome. It is virtually impossible to identify some insects to the level of species.

3. Insect orders: getting to know the top eleven

Take the 30 Insects Quiz

Consider each of the photos below. Ask yourself “what order does it belong to?”

Most (but not all) of the animals in the quiz belong to one of the 11 insect orders listed in the table above. Do you recognise the odd ones out?

Importantly, think about why you are assigning it to that order. For example, if you say “it’s a fly - order Diptera”, what is it about the insect that makes you think it’s a fly?

The table below presents the key characteristics which distinguish insect orders. The shortlist of ‘obvious characteristics’ shown in bold is often enough.

For some identifications, however, the obvious characteristics will not be enough. Perhaps your photo doesn’t show them, or your particular species is an unusual one. In such cases, consider the additional characteristics listed in the right hand column.

Recognising insects to order: a few more examples

Getting to know the insect body plan

The diagram below shows the basic body plan of an insect - helpful when reading insect descriptions in books or even in the table above.

4. Resources

Knowing the order of an insect allows you to take the next step: what family, genus, or even species?

There are two approaches:

1. systematically examine the features of different families, genera and species, using keys and scientific descriptions.

2. photo matching. Look for images that match or resemble your insect.

Both methods are valid, but photo matching is almost always the best first step.

Trawl a variety of websites and flick through a range of books.

Of course, the first place to check is the species list on NatureMapr, as you know that these are all local species. This can speed up your search no end!

We are building a list of resources for species identification, including links to a range of websites, including CSIRO resources and some very useful ‘amateur’ websites such as Brisbane Insects.

And not just insects. This resources list is relevant for all organisms.

Please let us know of any other useful resources you know of so that we can add them to the list.

One last thing.

During the Workshop I mentioned witnessing the mating of some quite magnificent bull ants, just the day before. And I took the two ants along to the Workshop, to show just how wasp-like such ants can appear.

Here they are in action.

Thank you to everyone who took part in this inaugural Workshop. We look forward to our next meeting.

Paul & Kerri-Lee

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Images: unless otherwise noted, all photos shown above were taken in our local region by Kerri-Lee Harris & Paul Whitington.