The most common jumping spider in our garden, Trite auricoma, with the remains of it most recent meal... a smaller T. auricoma:



Cannibalism,  animals eating members of their own species, is a pretty common and widespread behavior. Species in almost every phylum have been shown to occasionally (or frequently) eat members of their own species. Even herbivores like monarch butterfly caterpillars will eat any monarch eggs they encounter.

In spiders, the most well-studied form of cannibalism relates to mating. In a very few species male spiders will offer themselves as a meal to their mate. In so doing, males make sure their offspring get the best start in life, by providing their mother with a nutrition meal. They are often also posthumously rewarded by female, who reject other suitors and ensure the sacrificial male's legacy. The best example of this behaviour comes from the Australian red back spider (Latrodectus hasseltii). In this species males actually pirouette their way into their mate's fangs, and females take up the offer about 65% of the time. New Zealand's endemic red back relative, the katipo, does not exhibit this behavior (nor does the North American black widow, despite the name).

Such sexual cannibalism isn't known from jumping spiders (although females will certainly eat unwary males), and a wider (and earlier) shot lets you see that this was a case of a mature spider taking a younger one (males and females are about equally sized in T. auricoma).

Labels: arachnophilia, environment and ecology, jumping spiders, photos, sci-blogs, sunday spinelessness

So, last week my little old blog found itself in the middle of a national discussion abuot Ken Ring and his claimed ability to predict earthquakes. In this space of two days that post recieved a good deal more than a year's worth of The Atavism's normal traffic.

And now I have to tell anyone that subscribed to this blog in the wake of that article, hoping perhaps that I'd follow the news of the day and provide analysis of the key claims, that I mainly blog about bugs. I'm an invertebrate fan boy, and dedicate a post a week here to celebrating some creature from that ignored majority. Ninety five precent of animal species don't have a backbone, and the spineless multitude contains some of the most amazing creatures on earth.

Today, I'm going back to photos I took in Vanuatu over christmas and looking at my very favourite group of spiders - the jumping spiders (family Salticidae). Spiders get a bad rap generally, almost none of them pose any threat to us*, and absolutely none of them are going to go out of their way to get us. Some spiders, like the long-legged big-fanged Cambridgea in this post, seem to set of a revuslion somwhere deep within our brains, but others are just down right charasmatic. Jumping spiders are the puppies of the arachnid world: cute inquisitive and apparently unaware of how small they are. I've written about the group before, so lets skip right to the photos:

The big round forward-facing eyes are one of the charactersitc traits of the jumpers, because they are active hunters these spiders need to be able to cast a finely-focused image of their prey. Obviously, this one has used its eyes to good effect, I can't tell what it has clamped between its jaws (or chelicerae, if you want to be accurate). It has eight legs, which makes it a fellow arachnid, the body looks a little mite-like but the legs seem too long for that identification so I'm afraid I can't tell you anything more.

As much as it pains me to put up photos with zero taxonomic information, here's a another jumping spider of unknown affinity. This one was truly tiny, perhaps 3mm across the body, but quite happy to have it's host plant bent out of shape to allow a camera to intrude

That's it from me today. You should know that people much more skilled than I am have taken some terrific photos of jumping spiders. Alex Wild has a stunning ant-mimicking spider here, and Thomas Shahan is the acknowledged master in this field. Here's one example of his focus stacked images:

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*In New Zealand it's only the katipo and the (introduced) redback

Labels: arachnophilia, environment and ecology, jumping spiders, photos, Salticidae, sci-blogs, vanuatu

Today is going to have to be another photo-centered Sunday Spinelessness, after I managed to let most of my Sunday slip through my fingers between sleeping in and catching up on work. Still, this is a particularly cute photo so perhaps a shortage of words from me is not great loss:

The subject of this photo, a jumping spider, might look like it's staring away into the middle-distance. In fact, it's calculating. Most spiders are very shy and retiring, and at the first disturbance of their hideout they'll retreat to some dark corner and hide there until the coast is clear. Not so the jumping spiders, disturb a jumping spider and, likely as not, it will walk towards you and start to consider you as potential meal. They really remind me of puppies that are yet to learn they are much smaller than the big dogs, and any fight they pick with them isn't going to end well. This jumping spider seemed to think the camera wasn't much of a threat, so went after yet bigger game an jumped on to me:

After a while spent patrolling the knuckles and the base of my left hand it became clear nothing very much was going on, so the jumping spider lived up to its name an vaulted off in search of something more interesting while I cursed my inability to take a decent shot of it one handed.

Labels: arachnophilia, jumping spiders, photos, sunday spinelessness

Surely that's a face that will find its way into even the most hardened arachnophobes heart? The owner of those big round eyes is a female Helpis minitabunda, the Australian Bronze Jumping Spider. Last week I mentioned that the jumping spiders (family Salticidae) where my absolute favourite group of spiders, but the photos I used in that post didn't do much to show just how endearing these spiders can be (even when they are in the process of chomping down on a blowfly!)

Jumping spiders stand apart from most of their kin by being active during the daytime. Like the lynx spiders that have featured here before, they are active hunters which rely on good sight and surprise attacks to keep themselves fed. That lifestyle has led to features that make the jumping spiders so cute, huge forward facing eyes and a head that swivels around to follow you. Most spiders will react to an intrusion from some lumbering fool sticking a camera lens in their face by running away. Not jumping spiders, they'll eye you up in much the same way they would a passing beetle:

I managed to take a few photos of jumping spiders while I had all that fancy camera gear to play with. These photos don't do justice to the gear or their subjects, but here's a closer look at a couple of tropical jumpers (probably a female and then a male from a Menemerus species):

Labels: arachnophilia, environment and ecology, Helpis minitabunda, jumping spiders, photos, sci-blogs

A very quick post from me today, I've spend the weekend at the first Genetics Otago postgraduate retreat. Which was here:

Obviously, the meeting was mainly about talking with members of the most conspicuous vertebrate species on earth, but I did get a couple of chances hunt out some spineless creatures. My favourite has to be this guy, one of a few jumping spiders I found on saturday morning, sunning themselves on rocks high up on the beach:

The jumping spiders (Salticidae) are absolutely my favourite spider family, it's almost impossible not to anthropomorphise their huge round eyes and swiveling heads. Thankfully, once "my" jumping spider had calmed down he turned around and posed for me.

Labels: arachnophilia, citizen science, environment and ecology, jumping spiders, photos, Salticidae, sci-blogs, sunday spinelessness