For this blog post, we decided to watch a documentary about another member of the Hymenoptera group: the ant. Like bees (as previously discussed in our first blog post), ants too are a social species and their main objective is the protection and survival of the colony. The documentary tilted Ants: Nature’s Secret Power discusses the qualities that make different species of ants successful, but we will only focus on of these aspects:  the mutualistic relationships with other insects, such as aphids or carnivorous plants, and their organization of the colony.

Ants with a group of aphids.

Ants manage to attain food by making a “trade” between themselves and other insects. Adult ants require high-energy food and they acquire this through the aid of aphids, insects commonly referred to as plant lice that feed on plant sap and produce honeydew (liquid drops containing sugar). As a result, ants keep a colony of aphids on hand, since they are a consistent supplier of honeydew. In return for food, ants provide a home and protection for the aphids, and in some cases, transportation. Ants, for this reason, are given the label of “herders.” In the case of tropical ants, the “herders” carry their “cattle” to areas where the freshest plant sap is found.

Carnivorous plants, shaped like a jar or pitcher, from the Borneo island.

Another example of these beneficial relationships is that between carnivorous plants in Borneo and Camponotus ants (a species of the carpenter ants). These plants contain a poisonous liquid inside their jar-shaped leaves and attract a variety of insects through their sweet smell. Once the insect gets closer, it slips on inside rim of the plant’s interior which is very slippery and falls into the liquid that slowly digests it’s body. Camponotus ants feed on the insects that have fallen prey to the plant’s toxic liquid by walking on the interior, slippery surface and swimming through the liquid and carrying off the dead bodies. This remarkable feat is brought about by two abilities of the Camponotus ants: 1) capability of walking on this extremely slippery surface without falling and 2) power to swim and survive in this toxic environment. In return for the plants providing food, these ants protect the plant from other predators such as herbivores.

“Transport” leafcutter ants carrying the leaves back to their nest.

The documentary also mentions the organization of a species of ant, commonly referred to as leaf-cutters. These ants cut off the grass leaves, transport them to their underground nests, and feed them to a fungus that in turn provides food for the ants. There are two distinguished categories of ants that do this work. First, the “cutters” are larger, with strong jaws to chop down the grass leaves. If one ant struggles to cut it down, another ant will help it through teamwork. Afterwards, a “transport” or “runner” ant will carry these leaves and run back to the nest. These ants are generally smaller and lighter weight to facilitate their running speed.

The nest itself is constructed and intentionally designed by the ants, and is not an object that is already present in the environment. In a study done on leafcutters, scientists placed the ants in an simulated environment with only coarse and fine sand and clay, each time changing the amount of material available. On each occasion, the ants designed turrets (tower-shaped objects on top of nests), indicating their intentional creation and design of such mounds. These turrets are used in order to provide proper air ventilation throughout the underground tunnels. These ants are able to detect small differences in the density of the soil being used and air currents, and adapt their building design to their environment.

Overall, the documentary was very informative, clear to understand, and visually pleasing (very high-quality and clear images). It gave us a different perspective on ants and made us reevaluate them. They truly are very strong insects, and the documentary does a good job citing a variety of examples to support this statement (of which we only discussed a few). We didn’t really realize how strong ants are because they seem like such small creatures. However, their true strength arises when they are in large groups such as a colony, providing a great example of teamwork. Imagine how much more productive we could be if we worked as effectively in groups as ants do! Their strength was apparent when a colony of ants defended their nest from being destroyed by a bear, an animal that is so many times greater in size than an individual ant. Because the documentary listed a variety of reasons as to how they’re powerful, it didn’t go into much detail for each example, though that probably would have been better suited for a longer or multi-part documentary. Overall, a really great film!

Sources: 

Ants: Nature’s Secret Power

http://www.bbc.co.uk/nature/14993585

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Entomophagous parasites are insects that are parasitic on other insects; meaning that one organism attaches itself onto another organism, commonly known as the host, and collects nutrients for survival.  Parasites are defined as small organisms that complete most or all of their life cycle within a host, and many are capable of a high degree within host replication. Nearly all insects encounter other insect parasites within their lifetime. In general, arthropods that are considered parasitic are usually smaller in comparison to their host, they are only parasitic at the larval stage (unlike the pupal stages), each larva is limited to only one host and therefore results in the parasite to internally parasitize, and last but not least parasitic insects have a tendency to have a specific range of hosts. According to the Midwest Biological Control News, “(i)t is estimated that, on a world-wide basis, there are about sixty eight thousand species of parasitoids that are known to science and have been given a scientific name, (which) constitutes a little under ten percent of all known insect species.” One of the most commonly known and successful parasitic insect of these sixty eight thousand is the phorid fly.

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There are five parts to the process of parasitism for the phorid fly. First being that the parasite must locate where the host resides, then locate the host itself, pursue the host until accepted, distinguish between hosts that have already been attacked and hosts that have some potential to be parasitized, and finally establishing host regulation.  Besides developing an effective process, the phorid flies are considered successful parasites because of their parasite-host relationship with ants. Through this relationship, we can observe the process of natural selection, which is defined as, a process where organisms, which are adapting better to their environments or surroundings, tend to survive and produce more offspring. By “diminish(ing) the foraging activity of ants, frequently reducing the number and average size of foragers, and reducing the amount of food retrieved by a colony,” phorid flies not only obviously dominate in the relationship with ants, but also exercise natural selection by adapting to their environment.

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One question that might come up is why ants in particular? Out of all the insects in the world, why do phorid flies select ants as their hosts? Since host discrimination is a key part of the process of parasitism, phorid flies choose “social insects,”  such as ants, because of their blunt “ intraspecific chemical communication signals” that come in handy when trying to differentiate between potential hosts and already parasitized ones. In order to search for a host, phorid flies initiate the procedure by tracing the host’s habitat through the use of a host’s preferred environment. Since the phorid fly adapting itself to the host’s natural surroundings or environment, natural selection is explicated. Phorid flies proceed from there by detecting pheromones, which are the method in which ants communicate with themselves and are therefore manipulated as clues for their parasites to locate their potential hosts. Host regulation is established and maintained by even more cues, which include, “movement, host size, and contact chemical cues.” Host regulation is not only significant for parasitizing, but also can influence the success rate of offspring for the flies. Phorid flies hover over the ants, and then attack by inserting an egg underneath the ant’s exoskeleton once the process is close to an end or almost complete.

The effect phorid flies have on ants is noticeable in the fact that host regulation has the potential to “alter(ing) the physiology of the host in an attempt to facilitate growth or even alter(ing) host behavior to optimize nutrient intake or location within the external environment,”which therefore conveys the process of natural selection between the host-parasite relationship of the phorid fly and ant.

Sources: 

http://www.entomology.wisc.edu/mbcn/fea506.html

http://www.hindawi.com/journals/psyche/2012/380474/

http://www.hindawi.com/journals/psyche/2012/380474/

http://www.hindawi.com/journals/psyche/2012/895424/

Among the insects of hymenoptera, some exhibit highly developed social structures. An excellent example of this are honey bees, an insect that lives in hives and has a highly developed class system. Their roles in these communities include communication, gathering food, creating a nest, and caring for their young. Their organization finds many parallels with humans and their organization of the home, and in fact, the ancient Greek writer Xenophon compares a woman’s role in the house to that of a queen bee who directs the worker bee, produces offspring, and is in charge of food distribution in his house-managing manual titled Oeconomicus. Through this comparison, this passage highlights the various roles the queen bee, worker bees, and drones take on in their colonies.

The most powerful bee in the hive is the queen, as pictured above. There is only one queen in a hive, and she can live for several years.  During the spring and summer when the queen bee is ready to mate, she can lay up to 1,500 eggs in a day. She mates with many drones, up to 15, and stores their sperm in her spermatheca, which she will use throughout her life to produce new workers. She secretes a special pheromone, which establishes her position as queen of the hive by inhibiting sexual development of workers and promoting tranquility in the hive. It also helps attract drones to mate with. Queens leave their hives soon after reaching maturity to find drones from other hives to mate with.

Those bees born from the queen’s fertilized eggs become workers. Worker bees are also female, but are typically unable to mate. Instead they perform most of the work around the hive, gathering food, caring for larvae, and guarding the hive. If the hive does not have a queen, then worker bees can develop the ability to mate.

Bees born from unfertilized eggs mature into drones. Because of this, they only have one set of chromosomes as opposed to the two sets found in the other inhabitants of the beehive. The drones thereby serve as an example of the haplodiploidy that is characteristic of hymenoptera. Unlike the queen and worker bees, drones contain no stinger, pollen basket, or wax glands, and thus their main purpose within a colony is to reproduce with the queen bee. Drones are larger than other bees (as seen in the comparative picture above) and the only group of the three to be comprised of males. They tend to eat more than workers and do not usually gather food of their own. They tend to be thrown out of the hive if food is scarce, though not if the hive lacks a queen.

While queens and workers are both born from fertilized eggs of their queen, they are differentiated early on by the differing contents of their diets. All female larvae are initially fed a nutrient-rich substance called “royal jelly,” but those who are to become workers are soon switched to a mixture of honey and pollen known as “bee bread.” Only larvae that are chosen to become queens are given royal jelly throughout the larval stage of development.

Social structures are more developed in honey bee populations than in bumble bees ones. Bumble bees have small hives and less physical distinction between castes. A bumble bee queen starts a hive on her own by laying fertilized eggs and raising a number of workers. Eventually, her dominance will wane and some of the workers will lay unfertilized eggs that hatch into drones while others leave the hive to start their own hives. This reduced social structure extends to feeding patterns as well; whereas honey bees use a form of dance to communicate the location of food, bumble bees do not and learn to forage independently.

Consequently, these patterns of social structure are not uniform in the group hymenoptera; different species in this group display these social structures to a greater or lesser extent, reflecting the variety of features that has evolved among these insects.

Sources
https://agdev.anr.udel.edu/maarec/honey-bee-biology/the-colony-and-its-organization/
http://www.cals.ncsu.edu/course/ent425/tutorial/Social/bees.html