One of the pleasures of visiting Waiheke Island this summer was seeing native stick insects in abundance.
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One of the things I’ve noticed the last few years, is that a lot of common insects, have just stopped being common. Ten years ago, it was easy finding stick insects around this area of Auckland. Now they’re largely gone.
This seems to have happened also with Red Admiral butterflies. Once common in my childhood, I haven’t seen such butterflies in quite a while. I appreciate that in some areas they are likely to be still ‘locally’ common. They’re no longer however, quite as ubiquitous.
There also seem to be some loss in many of our native spiders. We have a very intriguing spider Celenia sp that is camouflaged extremely well. It looks like a bird-dropping. It also has the knack of only catching male moths. It produces the same sex pheromone as female-moths. Chemical warfare at its best. I haven’t seen any of these spiders now, since the 1980s. They used to be quite easy to find.
Now, what makes this a little more worrying, is that it’s not just me. I know of other people who are starting to wonder the same thing. Lots of insects, spiders etc that were nationally common, seem to have really disappeared.
I’d be very interested to learn if other people reading this blog have noticed the same thing.
Where are all the common insects going? Jul 05
5 Comments Leave a comment
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Brendan Moyle 1054 days ago
Well, bees don’t surprise me as they got a real knock after the Varroa mite arrived. There is some compensation with bumbe-bees and hoverflies.
I really don’t know, it might be a combination of several factors. We’ve had two new insectivorous paper wasps get established. Larger insects have always been vulnerable to rat predation. One of the key differences at Waiheke is the absence of possums, so other insect foragers (like the stick insect) might be doing okay.
I had been inclining therefore, to just too much predation and competition. But habitat changes or climate changes or pollution/pesticides could also be playing a role.
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David Winter 1054 days ago
Yeah,
My observational record isn’t quite as long as some other folks (not looking anywhere in particular…) but I certainly noticed the drop off in honey bees and the consequent increase in hoverflies and bumblebees. I’ve never seen a Celenia but a while back I gave a talk to a country school and one of the kids had one in a jar! (I suggested he might return it once his school project was over).
Don’t really know about the rest, perhaps we should institute a garden bug survey to compliment F&B and landcare’s garden bird survey? (Though, scaling up from a hundred or so bird species of which only a few are common to all invertebrates might be a bit of a problem…)
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Brendan Moyle 1053 days ago
I was wondering about something like the F&B bird survey. I’m not sure how practical it would be to set up something similar for NZ insects.
I got given (years ago) David Miller’s book Common Insects of NZ. But by the 80s, nobody was talking about ‘army worm’ being a problem (or common anymore). I suspect there are some long-term trends going on that are going to be very hard to detect.
In some years I’m not surprised at the declines of some arthropods. Weather conditions can be tough. I’m more concerned about say, the lengthening gaps at noticing some of these creatures that used to be ubiquitous.
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astrosteve 1048 days ago
Astronomers have been aware of the impact of artificial lighting on the night environment for some time. But others have noticed wider impacts including on ecosystems, human health and energy consumption. The book Ecological Consequences of Artificial Night Lighting refers to streetlights as “vacuum cleaners of the night” because of their impact on insects, birds and batts. The International Union for Conservation of Nature (IUCN) have established a Dark Skies Advisory Group to raise awareness of these issues. Its worth thinking about as newer energy efficient lamps may be worse for our insects as they tend to be more broad spectrum in their colour.
I’m seeing the same, everywhere. Butterflies and bees are both way down, despite there being lots of flowers about (well, fewer at the moment because of the season, but you know what I mean). I tend not to notice stick insects, and I confess I’ve never (knowingly) seen the bird-turd spider!
Maybe it is the neoncotinoids (or other pesticides), after all? Perhaps finding a way to reduce these would be a worthwhile scientific pursuit?