This morning I was searching around the internet for information about ants as I am interested in identifying the species of those that I have seen lately both in Pinar del Rey and in Jimena last week as their behaviour was quite different, the former colony were taking seeds into their nest, the latter insects.
On our recent outing to Sierra de las Nieves I had already asked one of the gonhs team, an entomologist, what he thought the former lot were up to and he explained that these would be Harvester Ants gathering grass seeds for their food stores. The workers doing the actual harvesting take back grass seeds whole, i.e still enclosed in a protective sheath.Once back at the nest the grain is extracted from the husk and taken in either to be stored or to be fed to the Queen or developing larvae. The unwanted parts are then discarded. He didn’t know why the beetles may have been there, but speculated they may have been finding food amongst the detritus. I have put the picture in again as a reminder (click on it to enlarge).
I am assuming then that these are Harvester Ants of the species Messor barbarus. I learnt more interesting stuff about these ‘granivorous’ ants, including the important role they play in seed dispersal.
The other insectivorous group (Jimena) were harder to pinpoint down, but I think they may be Argentine Ants, a species that has apparently spread all over the world. I checked the Iberia Nature website for anything they may have on ants in Spain and although I didn’t find what I was looking for I came upon this article, it is so amazing I have to share it:-
Unicoloniality and supercolonies
Most commonly, ants from different nests exhibit aggression toward each other. However, some ants exhibit the phenomenon called unicoloniality, where worker ants freely mix between different nests. A group of nests where ants do not exhibit mutual aggression is known as a supercolony — this form of organization is known as supercoloniality, and ants from different supercolonies of the same species do exhibit mutual aggression. Populations in supercolonies do not necessarily span a contiguous area.
Until 2000, the largest known ant supercolony was on the Ishikari coast of Hokkaidō, Japan. The colony was estimated to contain 306 million worker ants and one million queen ants living in 45,000 nests interconnected by underground passages over an area of 2.7 km2 (670 acres). In 2000, an enormous supercolony of Argentine ants was found in Southern Europe (report published in 2002). Of 33 ant populations nested along the 6,004-kilometre (3,731 mi) stretch along the Mediterranean and Atlantic coasts in Southern Europe, 30 belonged to one supercolony with estimated millions of nests and billions of workers, interspersed with three populations of another supercolony.The researchers claim that this case of unicoloniality cannot be explained by loss of their genetic diversity due to the genetic bottleneck of the imported ants. In 2009, it was demonstrated that the largest Japanese, Californian and European Argentine ant supercolonies were in fact part of a single global “megacolony”.
Another supercolony, measuring approximately 100 km (62 mi) wide, was found beneath Melbourne, Australia in 2004.
In the previous post I mentioned seeing a whole flock of Griffon Vultures that appeared to be circling over what I assumed to be food. Whilst on the Iberia Nature website, reading ‘Nick’s blog’ I came across this bit about Vultures and their problems finding food, complete with the fantastic photo:
18th Oct 2010 – A new Spanish study has highlighted the role played by vultures in reducing energy consumption in Spain, saving the annual energy use of an estimated 9,000 homes and preventing 193,000 tons of CO2 from being released in the atmosphere. Spanish livestock farmers produces 380,000 tons of carrion, whose incineration involves a high energy cost. An adult vulture consumes some three kilos of meat a week, with all vultures in Spain consuming some 10,000 tonnes a year. Unfortunately the strict EU rules, as a result of mad cow’s disease, force many farmers to incinerate dead animals in official centres at a high cost to both them and in terms of CO2 production. I’d be interested in knowing how much CO2 the vultures would save if and when the EU rules are eventually relaxed.
This is a precis of a report on another blog (La Cronica Verde): (link also on my front page)
Further discussion from Birdlife International on how they believe the EU rules could be changed: