Arthropods of the Ant Forest

Adaptations Among the Arthropods of the Ant Forest

The success of myrmecophyte trees has had a major impact on the ecology of forest environments. Plant-eating insects are comparably few and far between. To survive feeding from a garden that is under constant armed guard has required the evolution of a varied assortment of unique defensive adaptations.

Mites long ago evolved to fill the niches on Serina of Earth's aphids, as small, plump, and mostly defenseless arthropods which reproduce rapidly and feed on the sap of plants. Like aphids, they were originally slow and easily captured by predators, surviving by numbers alone. As the myrmecophyte trees developed, they were forced to develop better abilities to escape danger and did so with two pairs of greatly elongated hind legs that allowed them to flee approaching predators by catapulting themselves to a different perch in the manner of a flea. Such mites today, called sapspringers, are today one of the most cosmopolitan of plant pests.

The ability to leap far away from predators was highly beneficial to the sapspringers, but often these leaps are poorly controlled. While they can launch an individual to safety, they can also launch them directly into the path to another predatory ant or even entirely off the tree to the ground below. Improvements to the system were therefore still welcome, and one group of sapspringers in the early Pangeacene took this adaptation further and developed the second to last leg pair into a pair of flattened wings, with which it could control the angle of its leap and the speed of its descent. Simply by retaining the jumping motion of these flattened legs to flap these wings in the air, sapspringers by the middle of the Pangeacene were able to develop powered flight. While surviving primitive forms show that this was initially only usable for brief fluttering glides from one perch to another, by 240 million years PE forms have perfected their legs into proper wings and are competent flyers. Because they began with eight legs and adapted one pair into wings, they are superficially very similar to small six-legged insects and thus likely to be overlooked. The fact remains though that despite their small size and seemingly plain lifestyle, they are technically as unique and groundbreaking as the tribbats, and are a truly new, unique, and endemic clade of flying animal.

If other insects are to survive grazing on protected vegetation, they must also be wary and able to escape at a moment's notice, and it is so that the most numerous of treetop grazers in the Pangeacene are flying orthopterans known as flyckets. These cricket descendants retain the powerful chewing mandibles of their ancestors for cropping mouthfuls of vegetation but have reduced their hind legs in favor of highly developed flight abilities. Their wings are strong and suited to active flight, but unlike the broad-winged florgusts who were slow and graceful flyers the wings of flyckets are narrow, suited to fast, agile flight. Flyckets are predominately nocturnal and emerge from hiding in the forest leaf litter after dark when ants are relatively less active, alighting on the canopy trees in huge numbers, each spaced several feet apart. Their numbers and the way they align themselves serves to overwhelm the abilities of the ants to apprehend any one individual at once, causing them to disperse in smaller groups after each individual target and preventing them from forming deadly swarms. The visual acuity of the flycket is extremely acute, and with large eyes it can see almost all angles around it at once. As it is approached by the ants, it simply launches, circles around, lands a few feet away, takes another mouthful of vegetation, and repeats, while the ants spin wildly in circles trying to defend their host trees, managing to disable only a very small number of the total horde, most of whom fill their bellies and retire to the lower reaches of the forest by dawn. Even ants with very deadly venomous stings are unsuccessful if they cannot bite their intended targets before they escape, and in the end the ants are usually left able to do no more than to survey the damage. They will neatly trim away the injured stems and leaves every morning to reduce the chance of their host developing illness through the uneven wounds left by its nighttime assailants.

The sheer numbers of ants in the forests means that the insects themselves have also been adopted as a food source, not only by insectivorous vertebrates but also other insects. Many types of larger, wasp-like vesper ants regularly hover around myrmecophyte trees and pick off the individual eusocial ants, which they quickly disable by chewing off their heads. This is not always a one-sided attack, however, as some ants turn the tables and spray defensive jets of formic acid from their jaws at their would-be attackers. The same ants may also use artillery attacks to defend against herbivores, including flyckets, which respond by partitioning themselves further apart so that they cannot all be mobbed at once; the spray of a single ant or even a couple can be groomed away from the much larger cricket's body without causing harm, for it is only when a swarm operates together that the quantity of their weapon becomes deadly. Large browsing vertebrates are also targeted by ants aiming to protect their trees and this is probably the reason that the circuagodonts are still virtually absent from the sunflower forest. The forest is still the domain solely of many different sorts of herbivorous birds, for while circuagodonts have sensitive snouts and mouth tissues, the horny beaks, insensitive mouths, leg scales, and the specialized nictitating membrane of birds, with which they can shelter their eyes, leave them better suited to resist the ants' defenses.