Saturday, 21 September 2013

An Interest in Insects

Observing wildlife can be an inconvenient hobby, schedule-wise. If you've somehow managed to retain healthy human relationships throughout years of an obsessive wildlife interest, there will be nights where you must mingle with that most horrid of species - your fellow Homo sapiens. Plans to go spotlighting for possums or frogs may need to be postponed, and you certainly won't be getting up before dawn to see the birds in the National Park.

This is where an interest in insects comes in handy. Insects are 'ectotherms', meaning that their energy must partially come from an external heat source, usually in the form of light. Mid-morning as the sun climbs higher is a great time to go
looking for them, letting you have that potentially necessary sleep-in from the night before. Thank you, thoughtful ectotherms!

For this weekend's foray into the world of my six-legged buddies, I take an easy stroll around Ferguson Park, in the north-west Brisbane suburb of Enoggera. It's basically a small patch of lawn bordered by a weed-infested creek, though a glorious Tree Fern (Cyathea species) survives.

Creek along Ferguson Park perimeter. INSET: Golden-Orb Weaver and Grey Butcherbird

In this altered and degraded habitat, there's less opportunity for insects to hide, and the first thing I notice are their predators. Several different types of spiders abound here, including Golden Orb Weavers (Nephila plumipes) and a flowering bush full of juvenile Tent Spiders (Cyrtophora moluccensis). A Grey Butcherbird (Cracticus torquatus) also patrols the lawn areas, devouring low-flying insects.

Clear-sided Bush Cockroach
The survivors of this battlefield know to play it low and stick to what cover is available. Like its clever city cousins, this Clear-sided Bush Cockroach (Ellipsidion species) can recognise a good hiding spot when it sees one, finding shelter in the curl of a dry leaf. As I pointed out earlier this month, there are around 400 native cockroach species in Australia, and understandably, no guidebooks feature any more than just a handful of the most common species. The best reference material I can find is Peter Chew's excellent website 'Brisbane Insects', and even that thorough resource only identifies this particular cockroach to genus level.

Bolder insects in the park are usually the ones that can protect themselves somehow. In the afore-mentioned 'spidery' bush, Brown Flower Beetles (Glycyphana stolata) fly brazenly around the blossoms, reassured by the strength of their hard body armour. This protective casing over the wings and abdomen is one of the main differences between a 'beetle' and a 'bug', with the latter being able to defend themselves using their strong, piercing mouthparts instead. In the photo below, you can see the transparent, fragile wing of the Flower Beetle slipping out from underneath its armour as the little guy prepares for take-off. 

Brown Flower Beetle

If you can't be invisible or strong in the insect world, then it pays to be very quick! Around the perimeter of the park, Wide-banded Grassdarts (Suniana sunias) weave nimbly through the long grass. As their name suggests, the shape of their wings resembles a dart or an arrow and gives them great speed and manoeuvrability. What it doesn't give them, however, is long-distance flying power, which is a skill given to broad-winged butterflies like the Lemon Migrant (Catopsilia pomona). For this reason, the Grassdarts become quite territorial over their little patches of the park, defending their food plants from each other with aerial chases and wing displays.

Wide-banded Grassdart

An hour and a half of witnessing these tiny survival dramas sees me leave the park feeling restored in a way like no other, ready to tackle more human dramas and that inevitable Monday morning.

12 comments:

  1. nice little visit with your insect pals. :) love the grassdarter. looks a bit like our skipper butterflies. you can keep all 400 of your cockroaches. :)

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    1. Well we have a huge home-invading type here called the American Cockroach, so I don't know if that's fair! Haha! And yes, you're right, the Grassdart is a type of Skipper :)

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  2. HI Christian What an interesting post and I especially lovved the last shot.

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    1. Thanks Margaret, yes it was a very photogenic little subject!

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  3. Nice set of insects (and a spider!) do you get a time when you dont have them about up north?

    Cheers - Stewart M - Melbourne

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    1. Thanks Stewart, no we pretty much have them around all year but they seem to get extra busy and active once the days heat up again. Tomorrow will be 34C here so it's basically already summer!

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  4. Great humour in your post Christian. I've told my wife I am taking up bugs as well as birds now. I must say I am envious of your all round knowledge of wildlife. 400 cockroaches! - Yuk.

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    1. Thanks Phil! No need to be envious, I just do a lot more research than I let on. It really bothers me when I can't identify something down to species level - this used to be just a 'bird' thing but over the past few years it's extended to all the animal groups.

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  5. Me again - I think you may have more birds that I dont see than the other way around!!

    Cheers - Stewart M - Melbourne

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    1. Well you still have some lovely ones down south. I'd love to see a Cape Barren Goose! :)

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  6. Don't know how I missed this post - sorry! That Grassdart picture is phenomenal. Very disturbing about the number of cockroach species.....we only have three natives in the UK!

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    1. No worries, I wouldn't be stuck by the computer too often if I lived where you live - especially if I only had three cockroach species to contend with! ;-) Thanks for the compliment, that picture is one of my favourites!

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