Pretenders

“this isn’t right”…the officer said in a sombre tone. I tried to play the ignorance card and just looked at him blankly. “You have been here longer than a month”. No going back now… I decided, so I pulled all the stops; “I have a letter from the ministry of home affairs” I said importantly with a flourish. He looked at me uncertainly so I decided to press my advantage, “it is a written permission allowing me to stay an additional month”- I may have omitted the part where said allowance is only valid after confirmation by the chief immigration officer only after numerous unnecessary paperwork had been filed. “Alright, where is it?” Shit, shit, shit…he was he actually going to call my bluff. “In my bag” I said fearlessly (inwardly of course I was shitting myself) taking a step towards the door. The officer took a look first at me, then at the lineup of people shifting impatiently that he still had to get through and then nodded and tossed the passport at me. The bluff had worked, I was thrilled enough to almost make me forget that I had another 4 checkpoints before we reached our destination. I didn’t say a word to my companion lest I cement a bad impression with him before we had even started our journey. “There will be plenty of time later on to make a bad impression” I told myself.

So the minibus rumbled on…Jammed as we were, each pothole sent us sliding into one another. I felt like I was getting two lap dances simultaneously from my neighbours which wouldn’t have been so bad if they weren’t both slightly drunken guys who were half asleep and lingered a little too long in places they should not have lingered! Fortunately at the subsequent checkpoints, the attention to detail was a little lacklustre and I was just asked my name and then crossed off the manifest. The officers probably assumed that the checkpoints before them had already done their requisite duties and so I was waved on further and further into the country. The night bumped and jostled forward, the music blared from the tattered stereo system. Everyone complained and wanted to get some sleep but you can’t really argue when the driver needs the music to stay awake. So it blared out at us and again I vowed never to take another minibus. We arrived at the Kurupukari crossing and my companion who now hadn’t slept in 2 nights stumbled out of the minibus. I looked at his haggard expression and he was evidently in a great deal of discomfort. “What if we go first to Iwokrama? We can spend the day, recuperate…you said you wanted to visit there anyways”. He quickly agreed with my plan and so rather than travel onward we took the ferry across the Essequibo and then a canoe up to Iwokrama. Despite the fact that I had already been there for three weeks and was eager to explore new territory, the familiar always holds a certain appeal. And so I was glad to greet familiar faces. We rested for a few hours ate some breakfast and then went on a hike. I also chatted with some biologists there. They asked me if I could do a slide show of my photos for a small group the next day and I agreed (temporarily forgetting my mortal fear of public speaking).

Survival in the rainforest can be a difficult thing and insects like any other group have evolved a number of tactics to help them achieve this end. Several of the broader strategies are camouflage, aposematism and mimicry. It is this last strategy I’ll dwell on simply because I saw one of the most wonderful examples that I have come across before or since.

There are several types of mimicry but the one of concern in the present example is Batesian mimicry. This form of mimicry involves one species, the ‘mimic’ which has evolved a similar set of characteristics to a ‘model’ species. This definition is purposefully broad in order to encompass the diverse forms that mimicry can take. Essentially mimicry is designed to fool the senses. Hence tactile, visual, chemical and auditory senses all have their own followers who seek to ‘dupe and/or destroy’. Mimicry can be defensive in which an innocuous mimic poses as a more threatening model species, it can be predatory in nature or it can be both.  To best illustrate this example let’s take a look at a fascinating group; the ant mimicking spiders. These have evolved independently across a number of different families, a simple testament to its effectiveness as a survival strategy.

Ants are a common model organisms to imitate due to both their abundance and diversity. They are usually quite aggressive, and having evolved from wasps many groups retain a potent sting in which they may inject formic acid. For these reasons, many predators avoid ants. In this way ant mimics can avoid predation by passing unnoticed amongst the multitude of ants. However, a more sinister application of this subterfuge can be seen when they actually predate on the ants themselves. Passing unnoticed in their ranks, who will notice the odd ant that goes missing? It is a clever ploy which has led to increasingly convincing mimics.

Ant mimicking Sac spider (Clubionidae). These spiders make for fairly convincing mimics and come in a variety of colours which indicate species specificity. Their long front legs are typically held above their heads to imitate antennae and wave back in forth in rather convincing manner. The thorax is elongated like the petiole of the ant with a bulbous thorax.
Ant mimicking Sac spider (Clubionidae). These spiders make for fairly convincing mimics and come in a variety of colours which indicate species specificity. Their long front legs are typically held above their heads to imitate antennae and wave back in forth in rather convincing manner. The thorax is elongated like the petiole of the ant with a bulbous thorax.
Close up of Ant mimicking Sac spider (Clubionidae). These spiders make for fairly convincing mimics and come in a variety of colours which indicate species specificity. Their long front legs are typically held above their heads to imitate antennae and wave back in forth in rather convincing manner. The thorax is elongated like the petiole of the ant with a bulbous thorax.
Gliding ant (Cephalotes sp.), ‘model’ species, from Iwokrama rainforest reserve, Guyana.
Ant mimicking crab spider (Aphantochilus rogersi). An incredible mimic, from the shape of the body to the prominent dorsal spine. Iwokrama rainforest reserve, Guyana.
Here the spider can be seen with prey which it holds close to its head as a further act of behavioural mimicry. In this way passing ants will view nothing amiss and the scene will pass for two communicating ants rather than one that has been predated on. (Aphantochilus rogersi) with prey, Iwokrama rainforest reserve, Guyana.
Here the spider can be seen with prey which it holds close to its head as a further act of behavioural mimicry. In this way passing ants will view nothing amiss and the scene will pass for two communicating ants rather than one that has been predated on. (Aphantochilus rogersi) with prey, Iwokrama rainforest reserve, Guyana.

Of course spiders aren’t the only ones who have decided that ants provide a good solution to their survival woes; katydids, treehoppers, leafhoppers, mantids, Alydids and a large number of other insect groups have gotten in on the game.

Ant mimicking juvenile mantid. It is typically only in these juvenile stages while they are most vulnerable to predation that these mantids mimic ants. As they moult and grow larger, they have outgrown their models and become less convincing, and so they typically assume a more camouflaged form. Kaieteur national park, Guyana.
Ant mimicking Alydidae nymph. These insects too mimic ants while in their nymphal stage. Some remain so convincing that it is only the presence of a proboscis tucked away under their bodies which give them away. Iwokrama rainforest reserve, Guyana.

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