Leaf-veined slugs

In one of my day walks through the forest I reached down to dismantle a rotting piece of wood, to reveal some of the invertebrates that are hidden within.

Does not look like a slug at first glance

Does not look like a slug at first glance.

 

There are about 30 species of native New Zealand slugs, most of which are endemic to New Zealand. All have a characteristic leaf-vein pattern on their dorsal side, most likely for camouflage. This leaf-vein pattern is absent in introduced species. In addition, native leaf-veined slugs have only one pair of tentacles – unlike introduced species of slugs, which have two.

New Zealand slugs belong to the family Athoracophoridae. The one in the photo below belongs to the genus Pseudaneitea. The pale bumps on the surface of the dorsal side are called papillae. In some recently discovered species the papillae form retractable spikes. Very cool, however it is unclear what the spikes are used for.

Leaf-veined slug (Pseudaneitea schauinslandi)

Leaf-veined slug (Pseudaneitea schauinslandi)

 

More common are members of the genus Athoracophorus. Leaf-veined slug biology is poorly known, but they are thought to feed mainly on algae and fungi found on the surface of plants. In contrast to other slugs, these beauties do not feed directly on plants’ foliage, and therefore do not cause excessive damage to plants. I wonder if they are ever considered as plant pests.

Leaf-veined slug (Athoracophorus bitentaculatus) with body fully extended

Leaf-veined slug (Athoracophorus bitentaculatus) with body fully extended

Leaf-veined slug (Athoracophorus bitentaculatus) with body retracted

Leaf-veined slug (Athoracophorus bitentaculatus) with body retracted

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Leaf-veined slug (Athoracophorus bitentaculatus). They are just so adorable.

Leaf-veined slug (Athoracophorus bitentaculatus). They are just so adorable.

 

The slugs are nocturnal, and frequently can be seen mating on the surface of leaves. All terrestrial slugs and snails are hermaphrodites meaning they have both male and female reproductive organs, but they need to mate in order to fertilize each other’s eggs. Most slugs have an enchanting mating ritual, in which they hang down on a rope of mucus and encircle each other until they form a spiral with their bodies. Their reproductive organs are drawn and get entangled too, until eventually flattening, creating a translucent flower-like structure. The mating process in leaf-veined slugs seems a little less “exciting”. The two mates meet on the surface of a leaf or on a thick branch, and after a short period of time spent familiarizing with each other, they exchange sperm. In the photo below the male reproductive organ is visible (a slug’s genitalia is located close to the head), and these slugs are in the process of exchanging sperm. Once the exchange is completed, the slugs part and each one lays clutches of soft eggs in a moist protected place, such as under fallen leaves or in rotting logs.

Leaf-veined slug love (Athoracophorus antipodarum)

Leaf-veined slug love (Athoracophorus antipodarum)

 

Don’t mess with the Huhu

On my first night in New Zealand, I did something that I always do when I get to a new place – see which insects were attracted to light that was left on. The usual suspects are various species of moths, but sometimes also katydids, antlions and beetles.

To my surprise, the first insect that I found was a large longhorn beetle (family Cerambycidae). With a length of 50mm, hairy body, large mandibles and beautiful elytra reticulated in yellow, one could not miss it resting on the asphalt. I later learned that this was the huhu beetle, Prionoplus reticularis, New Zealand’s largest endemic beetle.

The huhu beetle, Prionoplus reticularis

The huhu beetle, Prionoplus reticularis

Detail of Prionoplus reticularis elytra

Detail of Prionoplus reticularis elytra

 

Portrait of Prionoplus reticularis

Portrait of Prionoplus reticularis

 

The adult huhu beetles do not feed and live for about two weeks only. These insects spend most of their lives in the larval stage, boring into and feeding on dead wood. They can become pests in sawn timber and logs, eventually destroying the wood and leaving just the outer shell. The larvae are considered delectable wild food and were traditionally harvested by the Māori people to be eaten raw or cooked (note to self: I need to try this). At the end of their growth the larvae reach an impressive body length of 70mm and create a chamber for pupation. The adult beetle emerges from the pupa after 25 days and uses its strong mandibles to break free from the pupation chamber in the wood. The whole life cycle can take up to several years.

The adult beetles appear during the southern hemisphere spring and summer (November to March). They start their activity around dusk, and many of them reach outdoor lights and well-lit rooms in their heavy flight. I often found mating pairs in close proximity to light bulbs.

 

Many people fear these beetles for no good reason (or worse – I heard people relate to these beetles as cockroaches). The adults look a bit scary with their enormous jaws and long antennae swinging from side to side as they walk, but they are harmless and not aggressive. Well, that is, if they are not provoked. They can still use their mandibles to bite, but their bite is a lot less serious than other bites I got while in NZ (for example, ground weta’s. Stay tuned!).

 

Huhu beetle (Prionoplus reticularis). He's coming to getcha!

Huhu beetle (Prionoplus reticularis). He’s coming to getcha!

 

NZ Forest critters – first impressions

The insects I am currently after in NZ are nocturnal (meaning they are active at night) – this ensures me some interesting encounters with animals that are usually shy and cryptic. I thought I would start by describing to you my few readers (most likely my friends, family, and if I am lucky maybe one or two of my former students) what my night activities are like at the moment.
So what kind of animals you can find while taking a night walk in the forest?
Surprisingly for me, the most common animal to encounter in the NZ forest during the night is not a cricket or spider, but representatives of a genus of cockroach. These relatively small cockroaches (15mm) belong to the genus Celatoblatta of which 16 species are known. Very similar in appearance to the northern hemisphere German cockroach, they occupy the leaf litter and low forest plants. I mainly found them on ferns, and although I cannot tell them apart, I am certain that I saw more than one species.

Forest cockroach (Celatoblatta sp.)

Forest cockroach (Celatoblatta sp.)

 

Another common insect active in the dark forest is the crane fly. Here too, several species are seen, but I am talking about a particular species. One that is so massive, especially during flight with its thick leathery wings, that often I was not really sure what I was looking at. Unfortunately I have no idea about the species name.

Crane fly (unidentified)

Crane fly (unidentified)

 

Slugs are also seen frequently, usually climbing on tree trunks, on logs and sometimes on leaves (lower left). The slugs I have seen so far are very different from the ones I know, and I will dedicate a separate post for them. Ground weta (genus Hemiadnrus, lower right) are common on tree trunks and low plants. A very interesting insect group and the core of my current study – they will receive more attention in future posts.

Leaf-veined slug (Athoracophorus antipodarum)

Leaf-veined slug (Athoracophorus antipodarum)

Ground weta (Hemiandrus "onokis") nymph

Ground weta (Hemiandrus “onokis”) nymph

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I will end this post with two creatures that are not as common as the ones above, but can be easily found with a little patience.

Antlions (order Neuroptera) are sometimes seen on the vegetation. This pair was sitting on a branch and were probably communicating using their antennae. It is a relatively large species, so at first I thought they belong to the family Myrmeleontidae. However, looking at their antennae, I see that they are simple and not curved as in Myrmeleontid antlions. Therefore I am guessing that these are big lacewings, but I am still not sure regarding the family or genus.

A pair of antlions (unidentified)

A pair of antlions (unidentified)

 

If you are lucky, you might stumble upon cicada larvae as they emerge from the soil and climb nearby objects to molt for the last time into adult cicadas. I was fortunate enough to see this beautiful individual drying its wings after molting. It belongs to the highly diverse genus Kikihia, with about 30 species. Unfortunately, further identification is very difficult because there is no identification key available to the species level. This is one of the most beautiful insects I have seen. Vivid green in color with red “socks”, and rows of golden hairs on the abdomen.

A newly emerged cicada, Kikihia sp., with the moon shining in the background

A newly emerged cicada, Kikihia sp., with the moon shining in the background

 

 

 

In New Zealand!

For the past three weeks or so I have been traveling in New Zealand, looking for suitable fieldwork sites for selected species of ground weta. It is now summer at its peak in NZ, the air is (usually) warm and the sun is scorching hot. This is quite a change from the frozen cold state I left Canada in. Although I enjoy the scenery and the lively creatures I encounter, I have to admit I was never a summer person. I prefer the cold temperatures, so in a way I miss the winter. However, I am aware that had I been in Canada now I would have wished for some warm sunny days. Got to take whatever I can.

Meanwhile, in Canada...

Meanwhile, in Canada…

Hello world, welcome to my blog!

A little late than expected, and due to repeating disappointments with terms and conditions of some online social networking services, I decided that I should open a blog where I can post about my interests and whereabouts.

I assume I have to introduce myself first, but that is what the about me page is for.
This will mainly be a photo blog where I will present my point of view on nature but also a place to talk about research highlights. I also have a great interest in popular art and design, and occasionally I will post about the link between them and the natural world.

Thank you for visiting and I hope you enjoy!