Monday, August 19, 2019

Millipede or Centipede?

First, let's look at the difference between a Millipede and a Centipede.

Both of these are under the same subphyllum Myriapoda, thus sharing a lot of similarities like a long segmented bodies with lots of legs. There are some general characteristics you can find to tell them apart.

Millipede Centipede
Have 2 pairs of legs per segment  Have 1 pair of legs per segment 
Slow moving Fast moving
(Feeds on decomposing matters)
(Hunts other animals)
More defensive, rolls up or foul tasting  More aggressive, attacks with a venomous bite 
Body usually more cylindrical Body usually more flatten
Shorter segments and legs Longer segments and legs

However, several of these are common characteristics but not 100% accurate to distinguish them. Some millipedes may look flattish and have longer legs which makes them look more like a centipede.

The myriapod in the photo above is another interesting example. It is in fact a centipede despite its slow movement and defensive rolling up behaviour similar to a millipede. I call it the Millipede Centipede for its mimicry towards millipedes.

Scientifically known as Edentistoma sp.  These genus of centipedes are really rare and not much are known about them due to the very few observation of them in the wild. To most forest trekkers, this would be easily ignored as it looks like a normal uninteresting millipede. It is not surprising that they hunt millipedes as well.

I was lucky to find one night on the forest floor in a mixed dipterocarp rainforest in Sabah, Borneo. So far this could be the first recorded on in the state of Sabah (Northern Borneo). The evolution of mimicry is truly wonderful. Hope to find these centipedes soon again.

Saturday, April 21, 2018

Suicide Bombers of Borneo

Recently, a new species of ant is being viralled in the news, especially in science news. The new species of ant (Colobopsis explodens) from Borneo, is said to be able to 'explode'!

When encountering a threat, the minor workers will raise their abdomen and bite on the attacking predator. When the larger predator (usually other larger ants) is being held down, these exploding workers will rupture and releases toxic secretions to kill or drive away predators. Other terms for this kind of action are Autothysis and suicidal altruism. These workers die in the process, sacrificing themselves for the greater good - to save their colony. This is similar to bees that dies after stinging.

The major workers of the colony are larger but they have a different role instead. These majors are tasked to guard the nest entrance, where they have modified heads to block the entrance from predators. Instead of giving them workers and soldiers with powerful mandibles or stings, evolution has decided to give them "suicide bombers" and "blockheads" instead. 

When I read about this news a few days ago, I immediately recognize the red ant portrayed in the photos. I am used to seeing them on wooden railings and on tree trunks in my hometown - Tawau, Sabah (Malaysia). I easily notice them due to their attractive bright red color. I have only seen them in primary forests as they are arboreal and associate with big dipterocarp trees only. Little did I know about their defense mechanism before this.

Photographed in Tawau at 2016

There are at least 15 species of exploding ants found in Borneo (from a study in 2017), all were placed under the Colobopsis cylindrica species complex group, and now more specifically in the C. saundersi species complex group. Colobopsis (formerly Camponotussaundersi is the most popular species of exploding ants, which was discovered back in 1889. Colobopsis explodens are quite abundant and easy to work with, that is why they are being studied in Brunei many years before finally being described as a new species.

Photographed in Tawau at 2016


National Geographic - 'Exploding Ant' Rips Itself Apart To Protect Its Own

Gizmodo - New Species of ‘Exploding Ant’ Discovered in Borneo

ZooKeys - Colobopsis explodens sp. n., model species for studies on “exploding ants” (Hymenoptera, Formicidae), with biological notes and first illustrations of males of the Colobopsis cylindrica group

Monday, February 12, 2018

The World's Largest Moth ?

The Atlas Moth (Attacus atlas) is considered the largest insect in the world, by surface area. Several of the world's largest moths are also from the same family - Saturniidae, such as Actias maenas, and Archaeoattacus staudingeri, which are also found in Borneo.

However, we will need real worldwide study to determine whether the Atlas Moth is really the largest species in the world? Archaeoattacus staudingeri and Coscinocera hercules are also quite comparable in wing surface area.

Do visit Mother Nature Network to read some of the largest insects in the world.

This moth is found by Wayne Tsu during the recent Wildlife Expedition in Tawau Hills Park. The expedition which is organized by 1StopBorneo Wildlife Association and funded by Adventure Alternative Borneo has yield many exciting findings from this area.

Sunday, February 11, 2018

Caption This !

I am thinking of starting a new blog post series called Caption This!

This is where I will share my photos which shows interesting behaviour that amuses us and makes us wonder what is the meaning behind the photo.

Let us start with this pair of Pacific swallow (Hirundo tahitica). 

What is going on with this couple? You can clearly see which one is the husband right? Why is one of them scolding the other?

Leave your creative captions in the comments below!

One more thing to share before I forget. National Geographic Yourshot currently has a photo assignment called CAPTION THIS too. If you have interesting photos like this that is suitable for the assignment, do upload it on the assignment page. There is one more week before the deadline.

Saturday, February 10, 2018

David and Goliath of the Spider World

It is quite shocking to see this Jumping Spider (Menemerus sp.) holding on to a (Heteropoda sp.) Huntsman Spider's leg.

Could the Jumping Spider really take down the large Huntsman? Penney and Gabriel (2009) has recorded a Holcolaetis jumping spider feeding on a Huntsman spider. This is indeed a great feat. However, the jumping spider found by Penney and Gabriel is feeding on a whole huntsman spider by itself. This Menemerus that I photographed is only feeding on a leg.

I posted this earlier in the Arachnology page to see what others think about this. Scavenging behaviour is suggested. There is indeed a dead Heteropoda spider body around 30cm away which seems to be where this leg originated from. Scavenging in other spiders has been studied before but it is rare in Jumping Spiders as Jumping Spiders have a very developed eyesight (compared to other spiders) to identify their prey visually. Few studies has been done to show that some Salticids do scavenge, usually in spiderling or when live prey are scarce. Phidippus audax can even survive until adulthood as a scavenger. However, this behaviour is not studied in the tropical countries as preys are abundant. There needs to be more explanation than just scavenging for this Menemerus case as I wonder how did this happen. Did the Menemerus just found a dead huntsman and decided to pluck its leg out? or was the leg already seperated? Another thing that was unusual is the distance (around 30cm) this Menemerus carried the leg from the original body. Unfortunately the lab tests on scavenging behaviour did not measure how far a Salticid can carry its scavenged meal away.

The genus of this jumper may be able to give an important clue. Several species of Menemerus has been recorded snatching foods from ants (Jackson et al., 2008; Cushing, 2012). These spiders will approach ants that are carrying prey or brood and will sneakily snatch the load off the ants' mandibles with great accuracy and speed. I have seen this before and it is indeed one of the funniest behaviour I have ever observed in spiders. After snatching the food from the ant, it will quickly run away to a safe distance to enjoy its meal. This will leave the ants running around confused and agitated finding their load suddenly disappeared. This kleptoparasitism behaviour may explain how the spider got hold of a leg that has been carried away by ants from the Huntsman's body. One problem is that I did not notice any ants trying to dismember the Heteropoda's body.

There is one final hypotheses I would like to share. I have regularly observed Spider Wasps in this area dragging Heteropoda Spiders after injecting them with a paralyzing venom. While being paralyzed, the weakened struggling movement of the Huntsman's legs may cause this Jumper to misidentified it a caterpillar or a worm. After grabbing hold of the Huntsman's leg, autospasy causes the leg to break off.

These are the best answers I can think of. The best evidence to understanding this case is still the huntsman body itself. Unfortunately, I did not examine the Huntsman Spider body closely so I am unable to tell the cause of death. So this case will continue to be a mystery.

Everyone is welcome to add their opinions and explanation to this.

Menemerus = Jumper = Salticid = Jumping Spider
Heteropoda = Huntsman = Huntsman Spider
Kleptoparasitism = A parasitic behaviour where foods are taken from another animal
Autospasy = The breaking off / separation of an animal's limb from the weak areas due to being pulled

Cushing, P. E. 2012. Review Article Spider-Ant Associations: An Updated Review of Myrmecomorphy, Myrmecophily, and Myrmecophagy in Spiders. Psyche: 1-23.

Horner, N. V. and Starks, K. J. 1972. Bionomics of the Jumping Spider Metaphidippus galathea. Annals Of The Entomological Society Of America 65(3): 602-607.

Jackson, R. R., Salm, K., and Pollard, S. D. 2008. Short Communication: Snatching prey from the mandibles of ants, a feeding tactic adopted by East African jumping spiders. The Journal of Arachnology 36: 609-611.

Penney, D. and Gabriel, R. 2009. Short Communication: Feeding behavior of trunk-living jumping spiders (Salticidae) in a coastal primary forest in The Gambia. The Journal of Arachnology 37: 113–115.

Vickers, M. E., Robertson, M. W., Watson, C. R., and Wilcoxen, T. E. 2014. Scavenging throughout the life cycle of the jumping spider, Phidippus audax (Hentz) (Araneae: Salticidae). The Journal of Arachnology 42: 277–283.

Wolff, R. J. 1986. Scavenging By Jumping Spiders (Araneae: Salticidae). The Great Lakes Entomologist 19(2): 121-122.