|Lucaina marginata and Lucaina discoidalis, two species of net-winged beetles|
When the Mesquite trees are blooming in the Tucson Mountains I sometimes find the catkins of single trees covered in net-wing beetles. They are nearly all mating pairs. They probably attract each other through pheromones. But there are usually beetles of 2 different species present. Pheromones of closely related species can be similar or identical, so there must be an additional process of mate recognition to match up the correct partners. Lycids are loaded with toxins, so these aggregations may not only allow the beetles to find mates but also protect them against predation.
Collops sp., Melyridae (Soft-winged Flower Beetles), Montosa Canyon, October
|Leaf Beetles Deloyala lecontii|
|Trichodes ornatus (Ornate Checkered Beetle)|
Approaching a female can be risky for males of aggressive predatory species that are used to taking prey that is hardly smaller than they themselves. Several groups of diptera (flies) have developed ritualized gift-giving which appeases the female. I am not aware that these big Robberflies actually do that, but this male did successfully grab his chance while the female was busy feeding on a Yellow Jacket.
|Desert Firetail pair mating in wheel position|
Prior to mating, the male moves sperm from his primary genitalia at the end of his abdomen to the middle of his body where he stores it in a secondary genital location. When he finds a female he grabs her neck/head/eyes with his claspers. Tandem position. She then reaches forward to position her cloaca against his secondary genital opening to receive the sperm. Their bodies now form the mating wheel.
|Hetaerina americana (American Rubyspot)|
|Leafcutter bee males waiting for females to hatch|
When I saw the bees swarming a fence post at the ASDM I thought at first that I had found the hive of a social species. But they seemed too frenzied for worker bees. They turned out to be male Leaf-cutter bees waiting for females.
Leaf-cutter bees are solitary, but a good nesting site with many deep tunnels (beetle holes) may attract many females. Each lays multiple eggs in those tunnels, eggs that will become females are placed deeper inside, prospective males more towards the tunnel entrance. The males hatch first. Then they hang around the entrance, waiting for the females to hatch. No matter that some will be their sisters. On thing is certain: no female will run this gauntlet and leave a virgin.
|Swarming Honey Bees|
While the bees are swarming and traveling to a new location they often rest in the open, all clustered tightly around the queen. At this stage the crops of the workers are full of stored honey and they lack aggression. The swarm I found was very small, which might indicate that these were Africanized bees, but I could approach closely without problems.
Drones (males) are recognizable by their large size and their big eyes - I have focused in on one in the right photo. Drones do not forage and don't get fed after the mating flight, so at times they can be found dying under the hive. This is no indication that anything is wrong with the hive in general.
|Acromyrmex versicolor pair|
While scouting in preparation for the BugGuide Gathering in 2013, I was caught in a July thunderstorm in Florida Canyon, Pima Co, AZ. Suddenly many insects were flying in the soft warm rain, most of them tumbling to the ground. There they quickly shed their wings and began running around in pairs. Soon predators like ants an birds began picking them up. But many couples escaped to find new underground nesting sites to begin a new huge family of Termites. Different from ants, wasps and bees, they will have a long fertile life as a couple ahead of them.
|Colliuris pensylvanica, carabids, and Anomola delicate, scarabs|