Collecting harvaester queen ants (Part I)
Half a year is almost over! Although it is still early to collect adult mantis in the wild, this is the right time for ant to perform their
nuptial flight, especially right after the first heavy rain in the summer. June 21st marked the first day of summer in 2011. Houston
region has not seen any heavy rain since mid May, so the back to back pouring rain on Wednesday and Thursday (22nd and 23rd
of June) not only brought reliefs to many people, it also initiated the nuptial flight of many ant species.
The particular species of harvester ants that I am looking for is the Pogonomyrmex barbatus, a large red ant that is common in
Bear Creek Park in Houston. This year I have a chance to collect the queen ants together with a graduate student from University of
Houston. Lara is currently studying the harvester ant colony habit, and required large amount of queen ants for her research, so I
was glad I could help her collect some queen ants, and enjoying the collecting experience.
The rain on Wednesday continue for almost the entire day, which deterred the nuptial flight. But the rain on Thursday ceased after
morning. Lara reported winged ants flying soon after the rain stopped. By 1 pm, the temperature was started to raise to 90F and
although it was still cloudy, there was many queens without wings running around the ground on the field, some close to the nest.
But I continued to see winged female coming out from the nest (see pic below).
Once a while, I could see winged ants (both females and males) sticking its head out of the nest entrance, before emerging
completely out of the nest. Once out of the nest, the winged queen ants will wonder around the nest for a minute or two before flying
away. The actual nuptial flight or mating place was unknown. I assumed most of the mating taken place in the air or tree. But I have
also seen few mating 'ball' on the ground. Due to the close proximity between nest of different colonies, some winged male will
actually 'invade' any winged queen freshly emerged from adjacent nest (this species does not in-breed), to form a mating ball (See
pic below), even before the winged queen has a chance to fly.
SOon after mating, harvester queens will lose the wings by scrapping the wings off using the hind legs. Immediately after that, the
queen ant will spend some time locating a good spot to dig in. I have noticed that the queen prefer to choose the ground which has
direct sunlight, instead of the muddy area under the tree shade. The reason was unknown, but I have also noticed that shady area
underneath big trees were fully 'infested' by fire ants, which is the harvester ant nemesis. COuld this be the reason? Queen ants
have to be quick in selecting the suitable spot to dig in, as there were always some fire ants moving around the field targeting the
wondering queen ants on the surface. The dreaded fire ants were merciless towards the queens. Some will invade the hole made
by harvester queen and drag the dismembered body out. Most of the time, the fire ant used the hole dug up by the harvester queen
and feast on the queen itself in the same hole, pretty gruesome. The fire ants has been the main reason why harvester ants is
becoming less in this part of the region, to the point where the Texas horned lizard which heavily relying on harvester ants had
became non-existence. SOme of the queens collected have fire ants clamping on the queen's leg or other body part, and these fire
ants will continue to hang on the queen's leg even it is dead.
From 2 pm to 4 pm, there were plenty of wingless queens on the ground looking to dig in, so these were easy to pick up. After 5
pm, collecting the queen ants will require a shovel as most have dug in at least an inch or two below ground. Fresh holes built by
the queen were easy to identify and very distinctive. The hole has an round entrance of about 5-7 mm in diameter, with clearing of
about 10-15 mm diameter around the hole, and pellet size dirt around the clearing (some queens only accumulated dirt on one
side of the hole), as shown in the pic below (part of the pellet sized dirt on the right side of the hole made by harvester queen was
accidentally stepped on by me!)
But collecting the queen after 5 pm was still relatively easy, just need a little patience. The queen will still be digging and removing
the dirt to the surface during that period, so the queens still have to emerge from the hole. That was the time when I 'kidnapped' the
queen <evil smile>. You can see the queen's about to emerge from the hole on the pic to the left, with a piece of dirt ball. The pic on
the right was when the queen was about the move back into the hole after dumping the round sized dirt.
Following is the short video clip of the queen emerging from the hole while digging more dirt out. (Click the pic)
The queen ants could sense the threat (or ground vibration) whenever I approached the hole, so the queen will not emerge from
the hole for a while. In that case, i would use the shovel to dig out the queen while she was still not too deep in and the soil was
still soft enough for digging. (From left to right)
In order not to hurt the queen, the shovel will need to get as deep as possible just in case the queen has dug a deep hole by then.
Once flipping out the pile of soil, queen can be seen hiding inside the soil, but due to the large size and its distinctive red color, the
queen will be picked up easily. The freshly dug out queen usually try to hide underneath the pile of soil that were just dug out, but
some will try to fight back with their jaw wide open (See last pic on the far right).