Ants are not commonly used as nicknames for sports teams. We imagine ants as tiny creatures that are easily stepped on and vaquished by larger creatures. Most teams prefer a more intimidating image such as the ever popular yellow jackets, insects that strike terror at fall picnics.
Some ants can be intimidating, such as fire ants, the nickname chosen in 2007 by the University of South Carolina, Sumpter. Ants are social insects that survive through teamwork, an obvious link to team sports. Dr. Les Carpenter, who offically announced the nickname spoke on this theme:
The Fire Ants represent more than a group of individuals, but a group which works together to very effectively achieve one common goal.
Another team with an ant mascot is the NBA developmental basketball team in Fort Wayne, IN, the Mad Ants. The Mad Ants is a histoical reference to an 18th century battle fought near Fort Wayne by General “Mad
hony Wayne; chosen by popular opinion also in 2007. The promotors apparently thought that a fire ant character was a more compelling mascot than the General (and the basketball uniform fits better over the ant than it would over the General’s Uniform). Mad the Ant was created. The cartoon ant with the pearly whites behind the threatening mandibles has several nominations as the scariest-creepiest-most original mascot.
Red Imported Fire Ants, Solenopsis invicta,
arrived in the Southern US in the 1930s from South America. They have spread throughout the South and dominate in grassland areas. Recently, a new import from South America, the Tawny Crazy Ants, Nylanderia fulva,
has arrived and is displacing the Red Imported Fire Ants.
How do the Tawny Crazy Ants withstand the Red Imported Fire Ants? The Red Imported Fire Ants have a venom that is highly toxic to most other ant species. This allows the Red Imported Fire Ants to dominate food sources and out compete other ant species. The Tawny Crazy Ants are able to charge into clusters of Red Imported Fire Ants and suffer no harm. How do they avoid the toxin?
The Tawny Crazy Ants produce a large amount of formic acid that they spread over their bodies. The formic acid reacts with the Red Imported Fire Ant toxin and neutralizes it. Having neutralized the major weapon that gives the Red Imported Fire Ants an advantage, Tawny Crazy Ants take the food resources and even live in the nests of Red Imported Fire Ants.
Malta Today informs us of a new art exhibit in Valletta, Malta. One of the featured artists, Moira Zahra, places insects in drawings for humorous effect. She relates an incident with women cooing over a toddler and imagined a humorous picture of women cooing over an insect instead of a toddler. Her illustrations are certain to bring a smile to an entomologist.
Illustration: Moira Zahra
Oak Honey Dew Gall
Photo: Brian Inouye
There are many species of gall wasps that make galls on oaks. Galls may appear to be a formidable defense, but the galls are susceptible to parasitoid wasps. The parasitoids seek a gall, drill a tiny hole with their ovipositor into the center of a gall and inject an egg into the developing gall wasp larva. Parasitoids can cause significant mortality. A better defense would be useful.
The Oak Honeydew Gall Wasp, Disholcaspis eldoradensis, gets defensive help by attracting ants. Ants tend a number of insects that secrete sugary honeydew. Disholcaspis attracts ants, not by secreting honeydew, but by inducing their oak tree hosts to secrete sugary sap near the developing gall. Ants feed on the sugary solution and attack parasitoids that land on the galls. Galls that are defended by ants suffer less parasitism than unguarded galls*.
*BRIAN D. INOUYE and ANURAG A. AGRAWAL. 2004. Ant mutualists alter the composition and attack rate of the parasitoid community for the gall wasp Disholcaspis eldoradensis. Ecological Entomology: 29, 692–696.
Black Swallowtail Caterpillar Resting on a Stem
There is increasing interest in how insects move because they serve as important models for robot design. The tobacco hornworm, Manduca sexta,
is one of the most studied caterpillars. Its movements have been closely filmed and documented. Griethuijsen and Trimmer* review locomotion in caterpillars and note that until recently, accepted models of how caterpillars move were not entirely correct.
Caterpillars have 3 true legs on the thorax next to the head. They have several pairs of prolegs on the abdomen. The prolegs have hooks at the tip that can strongly grip the surface. Large caterpillars are top heavy and must strongly grip a surface to resist rolling over. When crawling, one or more of the prolegs or thoracic legs may be lifted off the ground.
The caterpillar crawl starts with the terminal abdominal segment at the posterior of the caterpillar. Muscle contractions lift this segment off the surface and pull the segments forward. The contraction causes the segments next to the terminal segment to form a small hump as those segments lift off the ground. When the posterior segment has traveled one step forward, the terminal prolegs plant, grip the surface and anchors the terminal segment. After the terminal segment is planted, the muscles in the nearby segments relax and the hump moves forward. Backward movement is prevented because the terminus is planted.
Meanwhile, muscle contractions continue to move the hump forward and prolegs in the middle of the abdomen are lifted from the surface in turn and also move forward one step. Eventually, the hump reaches the thorax, and the thoracic legs are lifted from the surface and placed down one step forward. The movement is not hydraulic and does not depend on the fluid inside the insect. The movement is most similar to a spring that is compressed, forms a hump in the middle, then springs back to its original shape. Similarly, the caterpillar cuticle has elastic properties that cause it to return to its shape when muscles relax. Unlike walking in humans, the caterpillar does not push the prolegs and legs against the ground to move forward. Prolegs and legs are only for grip. The forward movement is generated by muscles pulling posterior segments forward.
*L. I. van Griethuijsen∗ and B. A. Trimmer. 2014. Locomotion in caterpillars. Biol. Rev. (2014)
Bumble bee hovers near bee balm
In Bumblebee colonies, there are at least two factors that control queen production: queen pheromone and the amount a food. The queen produces a pheromone that suppresses the development of larvae into queen bees. Only when the queen stops producing pheromone are new queens produced. However, the absence of queen pheromone is not enough to allow a female larva to develop into a queen. The female larva must be provided with extra food by worker bees to develop into a queen. In the presence of queen pheromone, larvae can be fed extra food, but they do not become a queen. Thus, queen production requires a change in behavior of the queen and the workers. Queen production is jointly decided by the behavior of workers and the queen.
The development of the reproductive system of many insects that are not social is also tied to nutrition. For example, the reproductive systems of both male and female adult squash bugs do not develop unless the adults feed on a host plant in the squash family. Other plants may provide enough nutrients to sustain the adults for weeks, but without a key ingredient found in squash, they don’t reproduce.
Colonies of the bumblebee, Bombus terrestrisare,
are founded by a single queen who mates in the fall and begins a colony in the spring. The young bumblebee queen builds a nest and cares for her brood until they emerge as adults. Her adult offspring assume the duties of foraging and care of the young. The queen produces a pheromone that inhibits development of the ovaries and egg laying in her female offspring. Her pheromone maintains them as a woker caste. If the queen dies or is removed from the colony, the workers are capable of developing into queens, one of which can gain control of the colony.
The queen pheromone also inhibits production of new queens. During the summer, the bumblebee colony expands the numbers of workers and brood. It is not until autumn that the colony will produce new queens. To produce new queens, the bumblebee queen ceases to produce queen pheromone. This allows some of her eggs to develop into queens. Males and new queens eventually leave the nest to mate.
The behavior of the workers changes in the absence of queen pheromone. Workers, who are unmated females, begin to lay eggs that become males. Competition develops between the queen and the workers. Neither the workers nor the founding queen will survive until winter and the colony dies. Many of the queens that were produced by the colony will leave the nest, mate, seek an overwintering site, and start new colonies in spring.