Introduction:
On a hike October 22nd I came across a recent Pogonomyrmex nuptial flight. It had likely taken place just after the rains had begun a few days earlier. Most queens were found in the process of excavating claustral nests though a few were still wandering on the surface of the dirt looking for somewhere promising to dig. The substrate was loose sand near old sand mines in Northern California. There were several large established nests of the same species in the immediate area. In a location the size of a football field I would estimate 10 - 12 established colonies interspersed with colonies of Messor sp.
I collected 11 newly inseminated queens and the following will be an observation in colony development from a single queen. This species is known to be fully claustral and I will be attempting to provide food to determine if that has an effect on colony size and growth. I have also somewhat convoluted the study by adding small bits of pine resin as an attempt to inhibit the growth of mold and bacteria in the vial.
Photos of the species from Ant Web via Wikimedia Commons - http://commons.wikimedia.org/wiki/Category:Pogonomyrmex_subdentatus
Methods and materials:
Each queen is housed in a small plastic vial with snap tight lids. The vials were previously filled 1/3 with plaster as a substrate and allowed to fully dry over a week to ensure a solid flooring. Before the queens were introduced 4 drops of distilled water were added to the plaster to provide humidity.
The vials are enclosed in an incubator made from a small 5 1/2 gallon glass aquarium that has been partially filled with distilled water and heated by an aquarium heater to 31° C. This establishes a 30 - 31° C relative temperature in the incubator and vials. The incubator is covered with a fit acrylic lid and encased with posterboard to create a dim environment. The poster board is attached with tape to create a hinged door to allow for observation.
Each vial is labeled with a unique ID allowing for notes to be taken on each queen during the colony founding stage.
As food items I will be using sources of protein (dead and previously frozen termites) along with seeds (mixture of grasses). It appears most grass seeds are highly nutritious and lack toxic chemicals. I found seeds in a garden supply store that had not been treated with any chemicals.
Baseline data:
In various papers and on websites I was able to find some general information about studies of Pogonomyrmex species. Most scientific studies kept colonies in the laboratory at approximately 30° C. This was shown to provide the best level and speed of brood development. Some studies seemed to suggest marked decline in the speed of brood development at 25° C. It was also shown that high levels of humidity were necessary during colony establishment with most studies keeping newly inseminated queens at 60% humidity. I should call out two things - one this is a hobbyist website and I don't have time to cite sources and two I don't have several pieces of technology I wish I did so I am trying to get approximate levels of humidity in the vials. I have been keeping an eye o the visual cue of condensation on the inside of the vial and balancing that to ensure the queen and brood won't drown in droplets that may form.
General observations:
The queens show signs of aggression when disturbed by movement. Upon collection until they were settled in the vials for two days they paced around with open mandibles. After two days they were more subdued though aggressive behavior resumes in bright light or with any strong vibrations or movement.
11/16/10 - Noticed that while some queens were picking at the seeds, most didn't show signs of eating however vial DP-IN6 had shelled all seeds and had eaten the contents. I added an increased number of seeds to this vial to see how she would react.
11/20/10 - Much more noticeable picking at the seeds this time but not enough time had elapsed to see if they would eat the whole seed or were just nibbling. As the egg and larvae counts show there are significant changes in numbers and my assumption is that the larvae are consuming eggs and at times other larvae, or the queen is. DP-IN8 had signs of chaotic scattering of the eggs about the vial. This may be due to the movement of lifting the vial out of the incubator and observing but none of the other vials had the eggs scattered, they were all in nice piles.
I should also note surprise at what happened in DP-IN10. Last time I added the 25 or so eggs from DP-IN7 after that queen died. I had expected her to adopt the eggs for the most part and to see more larvae and eggs present this time. Now the egg count is 3 with 1 less larvae than last time.
11/24/10 - Most seeds were either completely gone or picked at and eaten. I noticed one uneaten fruit fly in DP-IN2 but the others were missing (eaten) or so picked at they were unrecognizable. Due to colder house temperature the incubator was hovering around 28° C. I upped the heater to the max and will watch where it stabilized again. According to the thermostat it has a max of 89° F.
12/2/10 - Constant temperature of 31° C established since last edit. Most seeds were missing or showing signs of obvious eating. When disturbed, queens with pupae defend those first by picking them up and running around. Vial DP-IN8 still had scattering of eggs not in a well formed pile.
12/7/10 - I'm beginning to wonder what's going wrong with this study. I found 4 more dead queens today leaving me with 4 living queens remaining. I wonder if the artificial heat is to blame since these were fall flying queens who would be in chilling winter weather. While the vials are not too small I wonder if they are not providing adequate oxygen or perhaps the humidity in the vials is too low. Perhaps the resin is to blame?
At any rate, I hope the remaining queens make it to colony formation. I added much more water this time and left the vial lids loosely fit as to allow air and humidity levels from the incubator to enter the vials. I did note that of the remaining queens, none have resin and it is now 50/50 fed vs. unfed. One of the queens, DP-IN03 has only eggs and one, DP-IN02 has just a handful of eggs and larvae. Only one vial, DP-IN01 has a pupae which has colored up slightly. Fingers crossed this study ends with a successful colony...
12/9/10 - Slightly nervous so I am checking on them more frequently now. It appears the humidity has risen with the lids ajar. I state this since the plaster is now able to be dug in slightly whereas is was was solid and not possible for this before. DP-IN03 is trying to dig a bit. All the queens are still active and moving and today the first worker eclosed in DP-IN01.
Specific vial observations:
DP-IN1 -- No Resin
10/30/10 - No eggs present. Added 1 termite and 1 grass seed.
11/6/10 - Approximately 15-20 eggs visible. Added 1 grass seed and 3 drops of water to as plaster and vial were dry.
11/16/10 - 28 eggs and 2 larvae visible. Added 2 grass seeds and 2 drops of water.
11/20/10 - 10 eggs and 1 larva visible. Added 1 dead fruit fly and 2 drops of water.
11/24/10 - 25 eggs and 1 larva visible. Added 2 seeds, a pin tip droplet of honey and 2 drops of water.
12/2/10 - 35 eggs, 0 larvae and 1 pupa present. Added 2 grass seeds, a pin tip droplet of honey and 5 drops of water.
12/7/10 - 35 eggs, 0 larvae and 1 pupa present. Added 4 grass seeds (no traces remaining), a pin tip droplet of honey, 8 drops of water and 15 eggs, 1 larva and 2 pupae from DP-IN10.
12/9/10 - 12 eggs, 0 larvae, 0 pupae and 1 worker present. Added 2 grass seeds, a pin tip droplet of honey, 1 dead fruit fly, 1 small dead cricket and 6 drops of water.
DP-IN2 -- No Resin
10/30/10 - No eggs present. Added 1 termite and 1 grass seed.
11/6/10 - Approximately 10-12 eggs visible. Added 1 grass seed and 3 drops of water to as plaster and vial were dry.
11/16/10 - 20 - 23 eggs visible. Added 2 grass seeds and 2 drops of water.
11/20/10 - 30 eggs and 0 larvae visible. Added 1 dead fruit fly and 2 drops of water.
11/24/10 - 25 eggs and 0 larvae visible. Added 2 seeds, a pin tip droplet of honey and 2 drops of water.
12/2/10 - 0 eggs, 2 larvae and 0 pupae present. Added 2 grass seeds, a pin tip droplet of honey and 5 drops of water.
12/7/10 - 2 eggs, 2 larvae and 0 pupae present. Added 4 grass seeds (no traces remaining), a pin tip droplet of honey, 8 drops of water and 35 eggs from DP-IN11.
12/9/10 - 10 eggs, 2 larvae, 0 pupae present. Added 3 grass seeds, a pin tip droplet of honey, 1 dead fruit fly and 7 drops of water.
DP-IN3 -- No Resin, No Food To Be Added
10/30/10 - No eggs present.
11/6/10 - Approximately 7-10 eggs visible. Added 3 drops of water to as plaster and vial were dry.
11/16/10 - 20 - 23 eggs visible. Added 2 drops of water.
11/20/10 - 25 eggs and 0 larvae visible. Added 2 drops of water.
11/24/10 - 20 eggs and 0 larvae visible. Added 2 drops of water.
12/2/10 - 30 eggs, 0 larvae and 0 pupae present. Added 5 drops of water.
12/7/10 - 25 eggs, 0 larvae and 0 pupae present. Added 8 drops of water and 25 eggs from DP-IN08.
12/9/10 - 11 eggs, 0 larvae, 0 pupae present. Added 2 drops of water.
DP-IN4 -- No Resin, No Food To Be Added
10/30/10 - No eggs present.
11/6/10 - Approximately 15-20 eggs visible. Added 3 drops of water to as plaster and vial were dry.
11/16/10 - 11 eggs and 4 larvae visible. Added 2 drops of water.
11/20/10 - 7 eggs and 3 larvae visible. Added 2 drops of water.
11/24/10 - 20 eggs and 3 larvae visible. Added 2 drops of water.
12/2/10 - 20 eggs, 2 larvae and 0 pupae present. Added 5 drops of water.
12/7/10 - 5 eggs, 4 larvae and 0 pupae present. Added 8 drops of water and 30 eggs from DP-IN05.
12/9/10 - 6 eggs, 4 larvae, 0 pupae present. Added 2 drops of water.
Following Vials No Longer In Study - Queens Died
DP-IN5 -- Resin
10/30/10 - No eggs present. Added 1 termite and 1 grass seed.
11/6/10 - Approximately 10-12 eggs visible. Added 2 grass seeds and 3 drops of water to as plaster and vial were dry.
11/16/10 - 32 eggs visible. Added 2 grass seeds and 2 drops of water.
11/20/10 - 30 eggs and 0 larvae visible. Added 1 dead fruit fly and 2 drops of water.
11/24/10 - 30 eggs and 0 larvae visible. Added 2 seeds, a pin tip droplet of honey and 2 drops of water.
12/2/10 - 28 eggs, 0 larvae and 0 pupae present. Added 2 grass seeds, a pin tip droplet of honey and 5 drops of water.
12/7/10 - Queen was dead, no mold present. Pile of 30 eggs added to DP-IN04.
DP-IN6 -- No Resin
10/30/10 - No eggs present. Added 1 termite and 1 grass seed.
11/6/10 - Approximately 20-25 eggs visible. Added 2 grass seeds and 3 drops of water to as plaster and vial were dry.
11/16/10 - 11 eggs and 3 larvae visible. Added 6 grass seeds and 2 drops of water.
11/20/10 - 7 eggs and 3 larvae visible. Added 1 dead fruit fly and 2 drops of water.
11/24/10 - Queen was dead, slight mold on the discarded seed husks though none on queen. Pile of 12 eggs and 3 larvae added to DP-IN8.
DP-IN7 -- Resin
10/30/10 - No eggs present. Added 1 termite and 1 grass seed.
11/6/10 - Approximately 15-20 eggs visible. Added 2 grass seeds and 3 drops of water to as plaster and vial were dry.
11/16/10 - Queen was dead, no mold or other visible problems in vial. Pile of 25 eggs added to vial DP-IN10.
DP-IN8 -- Resin, No Food To Be Added
10/30/10 - No eggs present.
11/6/10 - Approximately 7-10 eggs visible. Added 3 drops of water to as plaster and vial were dry.
11/16/10 - 35 eggs visible. Added 2 drops of water.
11/20/10 - 35 eggs and 0 larvae visible. Added 2 drops of water.
11/24/10 - 25 eggs and 0 larvae visible. Added 2 drops of water + 12 eggs and 3 larvae from DP-IN6.
12/2/10 - 35 eggs, 0 larvae and 0 pupae present. Added 5 drops of water.
12/7/10 - Queen was dead, no mold present. Pile of 25 eggs added to DP-IN03.
DP-IN9 -- Resin, No Food To Be Added
10/30/10 - No eggs present.
11/6/10 - Approximately 10-15 eggs visible. Added 3 drops of water to as plaster and vial were dry.
11/16/10 - 33 eggs visible. Added 2 drops of water.
11/20/10 - 20 eggs and 0 larvae visible. Added 2 drops of water.
11/24/10 - 20 eggs and 0 larvae visible. Added 2 drops of water.
12/2/10 - Queen was dead, mold visible on gaster but no where else in vial. Pile of 12 eggs added to vial DP-IN10.
DP-IN10 -- Resin
10/30/10 - No eggs present. Added 1 termite and 1 grass seed.
11/6/10 - Approximately 10-12 eggs visible. Added 3 grass seeds and 3 drops of water to as plaster and vial were dry.
11/16/10 - 11 eggs and 4 larvae visible. Added 3 grass seeds and 2 drops of water + 25 eggs from vial DP-IN7.
11/20/10 - 3 eggs and 3 larvae visible. Added 1 dead fruit fly and 2 drops of water.
11/24/10 - 6 eggs and 3 larvae visible. Added 2 seeds, a pin tip droplet of honey and 2 drops of water.
12/2/10 - 7 eggs, 2 larvae and 1 pupae present. Added 2 grass seeds, a pin tip droplet of honey and 5 drops of water + 12 eggs from vial DP-IN9.
12/7/10 - Queen was dead, no mold present. Pile of 15 eggs, 1 larva and 2 pupae added to DP-IN01.
DP-IN11 -- Resin, No Food To Be Added
10/30/10 - No eggs present.
11/6/10 - Approximately 7-9 eggs visible. Added 4 drops of water to as plaster and vial were dry.
11/16/10 - 20 eggs visible. Added 2 drops of water.
11/20/10 - 17 eggs and 0 larvae visible. Added 12 drops of water.
11/24/10 - 20 eggs and 0 larvae visible. Added 2 drops of water.
12/2/10 - 23 eggs, 0 larvae and 0 pupae present. Added 5 drops of water.
12/7/10 - Queen was dead, no mold present. Pile of 35 eggs added to DP-IN02.
