Monday, April 2, 2018

It's Swarming Time!

Swarms of bees, locusts, gnats fill the imagination with awe and fear.
Dr Abe V Rotor
Biologically swarming is essentially a social act enabling members of a colony to share genes with others belonging to the same species but different colonies.

 

Migratory locust: swarm and close-up. (Acknowledgment: Internet)


 Nature has so timed swarming to occur simultaneously in order to enhance gene sharing which is vital to the survival of the species, otherwise in-breeding within the colony is perpetuated like brothers, sisters, marrying each other.
    
A kind of swarming is also observed among coelenterates (corals).  At a given precise time, eggs and sperms are released into the water in countless numbers, and there fertilization takes place, the resulting zygotes becoming minute hydras that will soon attach themselves to become new corals. In certain islands in the Pacific ghost crabs crowd the shorelines and beaches during a particular period of the year at a certain phase of the moon, and there mating takes place in a kind of orgy.  The gravid females then shake off their eggs in the water where they will soon hatch and initially become zooplanktons.  Very few of these survive to maturity.   

Swarming among winged termites (simut-simut Ilk.) is perhaps the most romantic, in fact it is called nuptial flight because in the sweltering night air  lovers meet, and then they descend and seal their vows.  The couple seeks a suitable place where they will establish a colony.  

Swarms of gamu-gamu (gnats and midges) become nuisance to communities in  sheer number, swarms of locust destroy fields of standing crops overnight, swarms of bees, especially the African bees, may send a whole community to abandon homes  and belongings. In the bible King Solomon halted his troop to let an army of ants pass by.  This could be the kind of ants we know that invade homes and schools, and there are killer ants that destroy everything on their path.   

Old folks attribute swarming to several reasons which science has tried to explain scientifically.   

·        Swarming is a seasonal occurrence dictated by a biological clock, and therefore timed with the life cycle of the species. (e.g. termites and ants).  This kind of swarming occurs regularly to a particular species.   

·        Certain organisms such as locusts (Locusta migratoria manilensis) are driven by necessity to gather into a swarm.  Small groups first congregate where food is available and then coalesce into huge numbers, mating and reproducing along the way, before turning into migratory swarms. This kind of swarming though unpredictable has historical records in a place.  It often jibes with the occurrence of widespread drought or with the El NiƱo phenomenon.

·        Ecological imbalance may lead to swarming such as the case of gamu-gamu swarming on Laguna Bay in the sixties.  Overfishing in the lake triggered a population explosion of gnats which constitute the main food of fish. Thus swarming is an indicator of the conditions happening in an ecosystem.   

Much of what we know about the subject can’t sufficiently explain pathological conditions where bacteria suddenly burst in numbers, or how fungi all of a sudden grow over an entire forest floor. Why do people move to cities?  Is urbanization a kind of swarming? Why did the Israelites turn to the golden calf, a symbol of fertility, after their deliverance from Egypt? Do we harbor the genes for swarming called orgy?

 A flock of swifts (Penablanca, Pampanga); brown finch or maya (Virac, Catanduanes). Members often cross flocks to share genes, and prevent in-breeding.  This phenomenon is applied in herds, pride (of lions), schools (of fish), and other social units.   
Colony of higad, tussock moth caterpillars (Lagro, QC); an army of hantik ants attacking a caterpillar (UP Diliman, QC).  Members of a colony are pre-destined into castes, but come swarming time and they are liberated to perform reproductive function. Hence ants and termites are liberated from their castes, leave their colonies and join the once in-a-year super swarm participated in by countless of winged members of different colonies. After the nuptial flight, pairs begin to form new colonies.  .
   Coy in frenzy at feeding time. Safari World (Bangkok,Thailand)  

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