An ant lion larvae

Discovering

Life…
-An ant lion larvae……









-A project by Atmeeya Nayak
2008-09


Introduction:
The ant lion was closely observed for many years with my own interest.
I had started the observation of the larvae when I was 12 years old. When I went to my grandparents place in summer vacations I had picked up this interest. I collected some 2-3 dozens of ant lions in coconut shells and fed them ant’s everyday.
One fine day as I went to observe them I found that the ant lion pits were missing and when I dug inside the sand I was surprised to find a small sand ball which was actually a cocoon. Along the years of observation I have obtained more findings and have discussed here.
Methodology:
• Field observation and laboratory rearing.
• Observations in Valley School and my grandparents place. (Western Ghats).
• To collect specimens for the activity, I used normal small twigs as I knew the technique of locating the ant lion and transfer it in a coconut shell containing loose soil or sand.







Setting-up an ant lion farm….for the observation.



Classification:
Ant lions are a family of insects given the zoological classification Myrmeleontidae. The name is rooted in the Greek word myrmex (ant) and leon (lion). The family Myrmeleontidae is part is part of the order Neroptera, translated variously as “nerve wings” or “net wings”.
Why are they called ant lions?:
Since it preys primarily on ants, the ant lion is metaphorically speaking, a “lion” among ants.
They are also called “Doodle bugs” because of the designs they make in the sand. As a doodle bug seeks an ideal location to dig its pit, it leaves meandering patterns that resembles the random “doodles” of a preoccupied artist. When it finally finds a place to dig it spirals deeper inside every spiral.
Where do ant lions live?
Pit-digging ant lions are easiest to find because of their distinctive, cone-shaped pits, which are often found in clusters.



Ant lions can be found in sheltered, sandy areas such as outside walls under the shelter of the roof, often sheltered from the rain.
Ant lions are typically most active during late spring and summer, although they may remain active during winter in warmer climates.



Making their pits in the shady area(Valley School)



My Observations:
• The habitat or location depends upon the season.
• In my grandparents house I saw them outside the walls which is protected by the roof as that place is affected by heavy rains.
• In Valley School even though they lie scattered everywhere throughout the year; I observed them clustered under a bench to protect them from the rains.
• It depends on the food availability.
• They prefer smooth and dry soil.
• I have also seen pits on pebbles with soft soil.
• They prefer shady areas.
Ant lion Larvae Behavior:
Digging the pit:
The ant lion larva digs its pit in dry, sunny spots sheltered from wind and rain particularly on south-facing slopes. The soil must be light and easy to shift. Pushing itself backwards, the larva first draws a circle on the ground; then it digs deeper and deeper down and spirals towards the centre.
The excavated soil is thrown out energetically with the head. It takes about 45 minutes for the ant lion to finish its funnel-shaped cone trap. It buries itself at the bottom so that only the head, with opened jaws can be seen and there it waits for its prey. If their pits are disturbed they rebuild it immediately. One can even observe the interesting sand flicking behavior.
My Observation:
• The size of the crater is related not to the size of the ant lion, but to its hunger, the longer it has gone without food, and the larger it makes its pit.
• Ant lions dig bigger pits in full moon.



The soil must be light and easy to shift….

The ant lion:



Taken out from its habitat….



An ant lion preparing itself to dig a pit….

Digging the pit:



Ant lion in the process of digging the pit; it pushes itself backwards….



Then it digs deeper into the soil and spirals towards the centre.



Capturing the prey:
When ants or other small insects come up to the edge of the crater, the soil slips and the prey slides down, straight into the large, curved, piercing-sucking mandibles of the ant lion. It seizes the victim, paralyzes it with the poison injected at the first bite and sucks out its vital juices. If the prey manages to escape or stops itself from sliding all the down to the crater, the ant lion accurately hurls a rain of sand at it, invariably causing the captive to lose grip and fall at the bottom.

Capturing the prey……



Each pit is a hidden minefield…!
Lurking beneath the sand…..
-The Ant Lion.



The target!! Mission accomplished!!

Discarding the body:
Once it finishes sucking the juices out of the prey, the ant lion uses the same throwing motion of the head that it used to catch the prey to fling its now lifeless body out of the crater.
What happens to all the food an ant lion larva consumes during its life?
When I kept ant lions in coconut shells I noticed small ‘sand lumps” in the sand which suggested that ant lions excrete some fluid during their larval stage.
Ant lions digestive tract lacks an external opening for solid wastes, so faeces accumulate within the body for the entire larval stage up to three years. Some of the waste is processed into silk and is used for making its cocoon.
Discarding the body….



The second stage of the ant lion larva:
One morning as I went to feed my ant lions I noticed that some of the craters in the coconut shells had disappeared or some had become shapeless having only deep sand but no crater. To see if they were there, I dug into the sand and to my surprise I found a small sand ball and no ant lion.
I realized that these were ant lion cocoons and I collected 4-5 of the cocoons. Ant lion cocoon resemble rabbit droppings covered with sand grains. They are often buried several centimeters deep in soft sand and are difficult to spot when u attempt to excavate them. It undergoes metamorphosis to form a pupa.
The rare photograph of an ant lion cocoon….



It undergoes metamorphosis into a pupa...



Ant lion cocoon resembles rabbit droppings covered with sand grains. They are often buried deep in soft sand and are difficult to spot when you attempt to excavate them.



The ant lion moves deeper into the sand to build its cocoon…

The third stage:
After about a period of about three weeks, a tiny winged imago (adult) emerges from the cocoon, leaving a small hatch at the opening and climbs to the surface. The adult ant lion usually emerges from its cocoon in the evenings. It is unable to fly just after coming out, so it climbs up the nearest plant or tree where it waits for its wings to expand and harden. After about 20 minutes the adult’s wings are fully formed. An adult ant lion may eat small flies or drink water, but its real purpose now is reproduction, not feeding. Its remaining life lasts less than a month on an average-enough time for it to mate and lay eggs.
Note: - My observation is limited to larvae only.



After about a period of three weeks an adult ant lion (sand dragon) emerges from the cocoon….







Finally the pupa nibbled a hole and flew away…without me noticing it…



Observing and capturing ant lions:
Observing ant lions in the wild:
Catching ant lions is a technique that one masters while studying it. For most people who try to catch it, they lose them. I use a twig to catch the insect and carefully excavate it trying not to hurt it in the process. The trick is to first locate its jaws at the bottom of the pit.



Taking ant lions out of their habitat:
Removing insects from their natural habitat is always a risky proportion. If one decides to take home an ant lion for study he/she has to be prepared to feed it regularly. I put them in coconut shells and fed them regularly. One can also observe the adult by keeping a net over the container when the ant lion enters its pupa stage. This ensures that you don’t miss it when it emerges out of its cocoon.



Searching for the ant lion…



Removing from the habitat…



Collecting them carefully…







Adding loose soil for keeping ant lion in container…







Ant lion farm ready for observation.
Myth, religion and science:
The earliest ant lions are described in literature as mythical creatures. Described in ancient Greek texts and later in medieval Christian bestiaries, these fictious “ant lions” became the focus of fantastic stories which fulfilled symbolic or religious functions in their respective cultures. In the period ranging from the 11th to the 13th, a scientific revival occurred.
The path to an accurate, scientific understanding of true ant lions, however, is just as fascinating and nearly as confusing as the history of the mythical ant lions. Early naturalists had to overcome translation errors and widely varying classification attempts. Even the development of a more universally-accepted taxonomic nomenclature did not eliminate disagreements over some ant lion genus and species names-disagreements which persists even to present days.
Early European scholars, typically members of the clergy, actually considered ant lions to be larger species of ants.Maurus wrote: “The ant lion is a small creature, extremely hostile to ants. It conceals itself in dust and kills ants that carry provisions. It is justly called formicaleon towards ant it behaves like a lion, although towards other creatures only like an ant”.
Swedish botanist Carlos Linnaeus wrote and introduced the group name Neuroptera for the first time. He was the founder of the nomenclature system
In the Twelth edition of Systema Naturae (1767) Linnaeus first proposed the generic name Mermeleon
Modern nomenclature:
Still, there persists much confusion over the use of the name Formicaleo. One scholar, Leraut, attempted in 1980 to overcome the confusion by proposing that the International Commission on Zoological Nomenclature should use its powers to suppress the names Hemerobius formicaleo and H.formicalynx, both of which was proposed by Linnaeus and to validate Myrmeleon formicarium(us) of Linnaeus. As of 1991 no action had been taken regarding this proposal.
Observed!!







The a.b.c of the ant lion:
Common Name: Ant lion
Class: Insecta
Order: Neuraptera
Genus and Species: Brachynemurus ferox
Physical Description: Larva: 1 ¾ “. Adult: 2 ½”
Range: Honnavara, The Valley School.
Habitat: Larvae live in sand traps.
Food: A larva eats any insect that falls in its trap.
Lifecycle: Complete metamorphosis- 4 stages.
Winter Survival: Hibernation.
Life Span: Unknown
Adaptations: Large jaws, ability to create sand traps.
Sleep Cycle: Diurnal.
Niche: Predator.

Observations and findings:
This study focuses on the following questions:
OBSERVATION 1:
Aim: To elucidate the relation between the feeding level and pit relocation.
Method: Artificial sans constructed in the field to observe the foraging behavior of a pit building ant lion larva.
Findings: Rarely changed the positions of their pits, though several ant lions had moved actively until they constructed pits.
The average feeding rate was 3 prey/day/pit, and about 60% of preys captured were ants.
OBSERVATION 2:
Aim: Whether they actively choose from a range of habitat types.
How pit structure varies with various biotic and abiotic factors.
Findings: It was found that ant lions tend to distribute themselves uniformly under both natural and experimental conditions, do
not have substrate preference but prefer shaded areas.
During monsoon they shift to sheltered areas.
They build larger cones in absence of food; trap efficiency is related to its size.
OBSERVATION 3:
Aim: To examine whether or not ant lion larvae concentrate into the area where they can capture more prey.
Method: I released four ant lions in a large container and divided that into a half. In one half I fed both the ant lions with
prey and on the other half no prey was fed.
Findings: The non-fed ant lions did not move into areas where prey concentration was increased.
Even under starved conditions they did not relocate their pits until death.
OBSERVATION 4:
Aim: Influence of soil illumination and soil temperature.
Findings: Pit constructed by ant lion are most frequently found in areas which are darker and cooler than areas exposed to
the sun. This supports the view that construction of pits in shaded areas is a response to temperature than light.
Field Study:



I have observed ant lions in their natural habitat also. In the Valley School I had chosen three places for my study where their population was more.
 Around Mahasagar
 Path leading to the amphitheatre.
 The Neem tree.
OBSERVATION:
 In mahasagar most of them had taken shelter under the benches. Under one bench I found around 38 pits!! In a small area. Most of the cocoons were found in and around Mahasagar area.
 There were no cocoons found near the neem tree or the path.
 Ant lions around neem tree were bigger as compared to the ones found at mahasagar.
 In the path area the pits were larger and deeper compared to the other areas.
 The cocoons were found near the mahasagar in the months of December-January.
 In the neem tree area the pits were scattered everywhere and there were many of them. I think it was because of the lose and light soil present there. Surprisingly the ant lions were not in a shady area.