I found this Golden backed Ant (Camponotus sericeus) and a tiny pharaoh ant (Monomorium pharaonis) on a fresh pod of Rattlepod (Crotalaria pallida) in my backyard. I was using my favorite macro rig consists of Canon EOS 5D Mark III with Canon EF 100mm f/2.8L Macro IS USM illuminated by Canon MT-24EX macro twin light flash. While the Golden backed Ant was activelt chewing the pod and feeding on it, pharaoh ant was just foraging around. Even though the larger golden back saw the pharaoh ant, it did not react at all.
The Golden Backed Ant (Camponotus sericeus) is the commonest ant in India. There is a distinct pleomorphism in these ants with the major worker like the one in the picture here measures 8-10mm in length while the median workers are 5-7mm. Minor workers are tiny at 3-4mm spend most of the time inside the nest. Major workers are black and opaque with granular appearance their broad head and mesosoma. The antennae, tibiae and legs are dark castaneous red. Gaster has dense silky golden pubescence and in some individuals silvery pubescence is seen. The node of the petiole is rounded and knob like. Median workers are similar to Major worker with lighter colored legs and antennae. The forage individually and recruit nest mates by tandem running.
Nest entrance differ to suit the vertical gradient. In mountainous region, distinct from scrub savannah habitat, these ants construct chimney like nests, tangential to the slope above the soil, to prevent water rushing into their nests. On flat grounds as well as closed canopy deciduous habitats their nest openings are on level with ground layer. In evergreen forests where they are less abundant they nest in soil under leaf litter. They tend aphids and feed on the extra-floral nectar.
The pharaoh ant (Monomorium pharaonis) is a small (2 mm) yellow or light brown, almost transparent ant notorious for being a major indoor nuisance pest, especially in hospitals. The pharaoh ant, who originated probably from Africa, has now been introduced to virtually every area of the world, including Europe, the Americas, Australasia and Southeast Asia. This species is polygynous, meaning each colony contains many queens, leading to unique caste interactions and colony dynamics. This also allows the colony to fragment into bud colonies quickly. Colonies do not display aggression toward each other; this is known as unicoloniality. Monomorium pharaonis is also notable for its complex foraging system, involving intricate trail routes maintained with several pheromones. It was the first ant species discovered to use a negative (repellant) pheromone. These chemicals are integral for communication in this species. Pharaoh ants are a tropical species, but they thrive in buildings almost anywhere, even in temperate regions provided central heating is present.
Pharaoh workers are about 2.0 millimeters, in length. They are light yellow to reddish brown in color with a darker abdomen. Pharaoh ant workers have a non-functional stinger used to generate pheromones. The petiole (narrow waist between the thorax and abdomen) has two nodes and the thorax has no spines. Pharaoh ant eyesight is poor and they possess on average 32 ommatidia. The antennal segments end in a distinct club with three progressively longer segments. This ant can be found almost anywhere in the world. It is a major pest in the United States, Australia, and Europe.
The pharaoh ant queen can lay hundreds of eggs in her lifetime. Most lay 10 to 12 eggs per batch in the early days of egg production and only four to seven eggs per batch later. At 27°C and 80 percent relative humidity, eggs hatch in five to seven days. The larval period is 18 to 19 days, pre-pupal period three days and pupal period nine days. About four more days are required to produce sexual female and male forms. From egg to sexual maturity, it takes the pharaoh ant about 38 to 45 days, depending on temperature and relative humidity. They breed continuously throughout the year in heated buildings and mating occurs in the nest. Mature colonies contain several queens, winged males, workers, eggs, larvae, pre-pupae and pupae.
Like most ants, sexual castes (those capable of reproduction) copulate in a “nuptial flight”. This is when environmental conditions are favorable to encourage mating and males and virgin queens fly into the air at the same time in order to find mates. After a short while the males die, and the queens lose their wings and find a place to begin her colony.
After a queen mates, she will found a new colony. This means that she will lay eggs and care for the first brood herself. After the first generation mature, they will care for the queen and all future generations as the colony grows. In addition to the founding of a new colony by a newly mated queen, colonies may also “bud”. This is where part of an existing colony carries brood to another “new” nesting site along with a new queen –often a daughter of the parent colony’s queen.
Like other hymenoptera, the pharoah ant has a haplo-diploid genetic system. This means that when the female mates, she stores the sperm. As eggs move down her reproductive ducts, they can either be fertilized, becoming a diploid female, or not fertilized, becoming a haploid male. Because of this unusual system, females are more closely related to their sisters than they are to their own offspring. This may explain the presence of female workers. The workers include food gatherers, “babysitters” of the developing eggs, and guardsmen/look outs for the nest.
The Pharaoh ant is omnivorous and their broad diet is reflective of their tolerance of different habitats. Pharaoh ants feed on sweets: jelly, sugar, honey, cakes, and breads. They also enjoy greasy or fatty foods such as pies, butter, liver, and bacon. Believe it or not, a preference of freshly used medical bandages attracts these ants to hospitals. These ants may find also their way into your shoe polish. In their natural environment, Pharaoh ants may be found enjoying a recently deceased insect such as a cockroach or a cricket. Pharaoh ants use chemical trails laid down by other workers in order to find food.