Annie Northfield

Dec 20, 2023

Madeira (December 2023)

A large part of the allure of Madeira is the year-round subtropical climate. In December, the temperatures are typically in the low twenties and the humidity and cloud cover are variable. For many holidaymakers the winter sun is a welcome break from the cold conditions at more northerly latitudes, and for the more entomologically-inclined, winter on this island is anything but wintry.

Our short time on Madeira this year was technically a research trip for an upcoming paper (which will be linked and described once published) but as always, I kept my eyes peeled and managed to see a plethora of interesting flora and fauna.

Because of the short duration of our trip, we wasted no time in getting out and about to see what could be found. On our previous trip to the island we had only managed to find Perez' Frog / Rã verde (Pelophylax perezi) near the beach at Porto da Cruz, so we had a pleasant surprise when we discovered them in the artificial ponds in downtown Machico.

Green Frog, Portuguese Millipede being carted off by ants, Garden Snail, Decollate Snail.

Other night active creatures were indicative of recent wet weather; the omnipresent Portuguese Millipede (Ommatoiulus moreleti) and several snails, including the common Garden Snail (Cornu aspersum) and a predator, the Decollate Snail (Rumina decollata). The common name 'Decollate' refers to the common state of the adults in which the tips of their shells are broken off, as shown in the picture above. Wikipedia intriguingly offered up the idea that the adults break the ends of their shells on purpose, but it took a bit of finding to get any supporting information for this statement. Rascop (1960) states that decollation is poorly understood, but that the upper whorls of the shell are fragile and break through normal wear and tear. However, the thesis also states that Cooke (1895) provides an 'amusing' account suggesting that the snails do in fact whack the upper whorls about as if to get rid of them. The internal organs of the animal are protected from dessication by a calcareous plug. Decollation is also known from other species.

I paid more attention to various spiders in the urban areas after discovering that the Noble False Widow (Steatoda nobilis) may have originally been native to Madeira before being spread around the globe. Apparently I had just filtered them out on previous trips, because they were everywhere in the urban areas, on buildings and around lamp posts. Another common species was the Green-fanged Tube Web Spider (Segestria florentina), with its beautiful bottle-green chelicerae. These spiders have also been distributed around the world.

DAY 1 - Machico

Our first day hike was around the town, up and down the hilly roads. It was about 22 degrees and quite humid, although the humidity dispelled as the day went on. One of the best finds of the morning was a set of beautiful elongate weevils, the endemic Lixus cheiranthi, which were sitting on brassicas in waste patches and garden edges.

The only shieldbugs of the trip were both also sat on and around brassicas: a very striking torquata form Nezara viridula, and numerous Ornate Shieldbugs (Eurydema ornata), both adults and nymphs.

We found a lot of Spilostethus pandurus feeding on various plants; all bugs were active only in the morning, and by early afternoon insect life became increasingly difficult to find. Just as common were the small, animated Adonis Ladybirds (Hippodamia variegata), which hurried about among the plant stalks. While admiring both of these insects, my eye was drawn to a stalk of grass in the bank behind them, upon which was resting a beautiful Monarch (Danaus plexippus) caterpillar, dressed in smart pinstripes which broke up its outline very effectively. Monarch caterpillars feed on milkweeds, in this case on a Gomphocarpus sp., which the Spilostethus seemed to be enjoying as well - perhaps topping up their chemical defences.

The large size of the caterpillar as well as its position slightly further away from the foodplant may indicate that it was looking to pupate. We saw two adult butterflies as well, one of which was incredibly vibrant and fresh, the other so tatty it was barely distinguishable as a Monarch.

I photographed a rather basic looking fly with a nice pattern that caught my eye, without really thinking much about it. I then wondered why I'd photographed the fly in the first place, since I don't often bother with them, and looked back at the picture out of curiosity. In fact, seemingly without knowing it, I had photographed a species I had only recently been reading about: the Stable Fly (Stomoxys calcitrans), beloathed by livestock and unfortunate humans alike. The pokey stick emerging from under the head between the eyes is a giveaway (the name means 'sharp mouth' + 'kicking'); a savage mouthpart for sucking the blood of mammals. I wondered whether I had somehow subconsciously registered that this was a Stable Fly before photographing it, or whether this was one of those 'yellow car' scenarios, in which you read about something once and then start seeing it everywhere.

The medium-sized, beautifully spotted katydids (Phaneroptera sp.) were prominent in the roadside vegetation. They moved delicately, picking their way through the grasses, and jumped suddenly away with surprising power when disturbed.

Finally, when resting at the side of a footpath and watching the undergrowth, I noticed that the thick, glabrous grass stems around me were colonised by a small but colourful beetle, the Cereal Leaf Beetle (Oulema melanopus) and its globular, well-camouflaged larvae, which can become a serious pest of cereal crops.

DAY 2 & 3 - Ponta de São Lourenço... x2

We did the Ponta de São Lourenço hike twice during the trip, which was particularly interesting with regards to the climate and vegetation condition. The last time we visited in winter (several years previously), the vegetation was largely dry and brown; the invertebrates were all concentrated heavily underneath rocks, where the humidity was higher. This year, the weather had been wetter prior to our arrival and the vegetation was still lush and verdant - there were consequentially fewer invertebrates to be found underneath the rocks, but far more common species out and about in the undergrowth.

Portuguese Millipedes were by far the most common invertebrate encountered, walking across the path in their hundreds, aggregating where others had died, eating, mating, and so on.

Above: I'd never seen such a small male mating with a female before - he must have thought he'd hit the jackpot!

The spider fauna was mostly familiar species, with the Banded Garden Spider (Argiope trifasciata) dominating in the grassy areas, making strong and somewhat haphazard webs which created little clearings between the undergrowth. The real champion of the messy web was to be found in the urban areas, tangled among the Strelitzias: the Tropical Tent-web Spider (Cyrtophora citricola). This extremely adaptable and somewhat social species creates incredible shapeless, untidy-looking tents that can cover entire plants. During the day the spiders tend to remain largely immobile, doing most of their hunting and feeding during the night.

In the wilder areas of the headland, the smaller Gorse Orbweaver (Agalenatea redii) could be seen in their delicate orb webs at the sides of the trails, while under the stones were the fat, glossy wolf spiders, Hogna insularum. While rolling a rock back, I made the mistake of trying to get one to move out of the way by gently poking it with my finger, expecting a pretty calm reaction. Instead the spider turned with an agility I believed it to be incapable of, flicking my fingernail with one chelicera and raising its front legs. The message was crystal clear: do not poke my bottom! I was quite lucky to have used the back of my finger, as a bite on the fingertip from a chunky wolf spider might have put a slight damper on my morning.

Above: Banded Garden Spider, Gorse Orbweaver, Tropical Tent-web Spider.

There were more snails and slugs than last time, including the distinctive Leptaxis groviana with its textured shell and the small, elongate Amphorella tornatellina, with a subspecies (A. tornatellina minor), possibly the ones pictured below, endemic to the headland.

Above: Leptaxis groviana and Amphorella tornatellina.

One thing that never ceases to surprise me is how recognisable certain species are across the board. I see Devil's Coach Horses (Ocypus olens) regularly in the UK, mostly on arable field sites and grassland. They are impressive beetles, common across Europe, north Africa, and in some areas of the US. They are common on the headland, and despite their apparently nocturnal hunting habits, seemed perfectly comfortable walking around during the day.

Devil's coach horse beetle in defence position

The other comparably large and fierce looking beetle present on Ponta de São Lourenço is Scarites abbreviatus, an endemic scaritine beetle with the typical pedunculate body of the group: thorax and abdomen separated by a narrow extension of the mesosternum, probably allowing for greater flexibility in their under-stone, sandy or subterranean habitats. This one was just inland from the beachfront, terrorising its prey underneath semi-buried stones in the sand.

On the little Cais do Sardinha beach at the end of the headland was an enormous pile of driftwood, possibly piled on the side of the beach to prevent the strandline from preventing beachgoers from sitting down, or funnelled into one end of the beach by the tide. This large pile of smooth wood had become some sort of lizard fortress, with the lizards flitting back and forth underneath the sticks and between the cracks. Out of the corner of my eye, I happened to notice another, rounder shape disappear between the sticks of the woodpile - a mouse. House Mice have been on Madeira for a long time, introduced by humans potentially up to a thousand years ago. I had seen these mice here before, and noticed that their coats were very light and sandy-coloured, but never managed to get a picture. On this day, while relaxing, I decided to try and lure one out with some pieces of croissant from my lunch. I sprinkled some crumbs at a spot between two rocks where the mouse had passed through a couple of times, and waited. The wait was complicated by the fact that the lizards, who had already been trying to get inside the open lunch bag, quickly discovered where the crumbs were and stole them, so I had to keep waiting until they had all gone before putting a few more out. Eventually, I got my result: the mouse became emboldened and kept coming back for morre crumbs. I'm fairly sure it would have taken them from my hand (had I felt the inclination) but I didn't fancy a nip from a rodent on this holiday, particularly when it took a bit of an interest in the finger operating the camera below!

The photos don't show it incredibly well, but the fur colour did seem to be particularly washed-out, in some lights almost gingery looking. I presumed that this is to do with the relative isolation of this particular population, although I haven't found any resources to corroborate this theory.

The eponymous Madeira Lizard / Lagartixa-da-Madeira (Tiera dugesii) is the hallmark reptile of the island, and can be seen absolutely everywhere, from the sea-level beaches to the highest point. Not only are they also at least semi-social and extremely tolerant of each other, but their food preferences seem to be highly unfussy, from the typical insects and nectar to fruit and people's lunches.

On our final evening stroll and nightwalk around the town, we climbed the steep path on the western side to examine a face of columnar rock and have a final bird's eye view of Machico. I noticed a few new non-native plants, including Bugweed (Solanum mauritianum) from South America, and Bermuda Buttercup (Oxalis pes-caprae) originally from South Africa. The distinction between non-native and indigenous vegetation on Madeira is quite pronounced, the latter favouring higher elevations and more challenging terrain such as clifftops. I found myself feeling quite philosophical about the alien species, with a certain begrudging acceptance of their beauty and resilience in a landscape that was a very long way from their original homes.

The weather was calm, neither cool nor warm, with a mere whisper of breeze in an otherwise still and humid atmosphere and the low hum of sporadic traffic in the distance. I watched the clouds rolling over the hills as dusk gathered, and listened to the crickets chirping quietly from the side of the road as it started to get dark.