-Sristi Raj Rai, Amity University Kolkata
The one thing that should be wished for, when stuck in tropical or subtropical regions, is protection against powerful trap-jaw ant’s strike. Trap-jaw ants (belongs to Strumigenys genus) are omnivores that hold the speed record for second fastest accelerating predator appendages (recorded using high-speed video techniques) after the Dracula ant.
The pair of the large straight mandible (mount part) can open up to 180˚ and the inner hair lining senses the prey that triggers the jaws to snap shut like a trap (as the name suggests). If one bite is not enough then the jaw can restore itself to its open configuration, ready to snapback again like a spring. The ants can also use the power of their jaw to acrobatically fling themselves away (almost 20x their length) from their predator. Not only that, the head bearing the jaw-muscles is capable to carry out slow movements too (e.g. building the nest).
If you are already considering it as deadly, then hold on and imagine their power getting evolved by 7-10 times, independently across the world. The latch system stores elastic energy and releases it as kinetic energy when functioning. Study shows that by making some minor changes the simple ancestral gripping mechanism drastically changes into a trapping one. Now, exactly how this evolution took place? To answer the question, major muscle reconstruction in the animal’s body part and also the diversification in terms of length as well as the wideness in the opening, lead to the current ultrafast state. Did the evolution take place all of a sudden? No, it did not because there were intermediates forms closely resembling the ancestral part which went unnoticed.
The researchers also constructed an evolutionary tree to point out the association between the species. They also worked on 3D imaging and modelling the ants. The imaging was done by micro-computed tomography (CT) or microtomography scanners. Even after knowing the morphological evolution, there are unexplored areas – how different sizes and shapes of jaws affect their hunting patterns, is the genetic makeup to build all kinds of traps the same, etc. Thus, the group plans to move forward with the genome sequencing of the individuals in the Strumigenys genus to shorten the genetic and morphological gap.
Source: “Functional innovation promotes diversification of form in the evolution of an ultrafast trap-jaw mechanism in ants” by Douglas B. Booher, Joshua C. Gibson, Cong Liu, John T. Longino, Brian L. Fisher, Milan Janda, Nitish Narula, Evropi Toulkeridou, Alexander S. Mikheyev, Andrew V. Suarez and Evan P. Economo, 2 March 2021, PLOS Biology. DOI: 10.1371/journal.pbio.3001031
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