Lampade e lampadine come alleati nella caccia quotidiana, ponti tra vite in dipendenze interconnesse. La natura sembra eleggere relazioni piuttosto che individui, niente si crea da solo. Chiediti quante moltitudini contieni.
Lamps and lightbulbs as allies in daily hunting, bridging lifeways in entangled dependency. Nature seems to elect relationships rather than individuals, nothing makes itself alone. Ask yourself how many multitudes you contain.
Nome scientifico: Amaurobius erberi (Keyserling, 1863)
Global distribution (WSC 2021): Canary Is., Algeria, Europe (not in UK and northern Europe), Turkey, Caucasus
Caratteristiche anatomiche: L’A.erberi è un ragno di taglia media che va dai 5 ai 10 mm, dall’aspetto robusto e tozzo e colorazione generale scura, tendente al marrone grigiastro. Non ha una colorazione dalla fantasia peculiare, infatti ad occhio è praticamente indistinguibile da A.similis e A.fenestralis. Per una corretta identificazione è necessario osservare i caratteri genitali (palpi nei maschi ed epiginio nelle femmine), che in generale nel mondo dei ragni sono specie-specifici.
Comportamento: Tessitore di ragnatele tubolari, che si estendono in orizzontale, e vengono costruite fra le spaccature della roccia o sui muri. Proprio all’interno del tunnel di seta, il ragno attende la sua preda ignara, che urtando i fili che al suo ingresso si sviluppano in verticale, come colonne, allerta il ragno della sua presenza, a cui consegue un attacco immediato.
Anatomical features: The A.erberi is a medium-sized spider ranging from 5 to 10 mm in size, with a robust and stocky appearance and general dark colouration, tending to greyish brown. It does not have a distinctive patterned colouration, in fact to the eye it is practically indistinguishable from A.similis and A.fenestralis. For correct identification it is necessary to observe the genital characters (palpi in males and epigynia in females), which in general in the spider world are species-specific.
Behaviour: Weaver of tubular webs, which extend horizontally, and are built between cracks in the rock or on walls. Right inside the silk tunnel, the spider waits for its unsuspecting prey, which, by bumping into the threads that develop vertically, like columns, at its entrance, alerts the spider to its presence, which is followed by an immediate attack.
Naturalists have long been fascinated with the practices through which plants lure their insect and animal pollinators. The orchids are one large family of plants that have garnered significant attention for the techniques they use to secure fertilization. Charles Darwin was among a handful of nineteenth-century naturalists who invested extraordinary time and attention documenting encounters among orchids and insects.
After years of intensive study, his 1862 treatise On the Various Contrivances by Which Orchids Are Fertilised by Insects exclaimed: “[H]ow numerous and beautiful are the contrivances for the fertilisation of Orchids.” In his description of the species Orchis mascula, he insisted, “[I]n no other plant, or indeed in hardly any animal, can adaptations of one part to another, and of the whole to other organisms widely remote in the scale of nature, be named more perfect than those presented by this Orchis” (28). From the vantage point of his theory of natural selection, orchid and insect bodies were perfectly articulated to one another, serving both orchid reproduction and insect nourishment. Darwin delighted in his ability to discern the mechanical functionality and utility of orchid Differences flowers and took this as a demonstration that even beautiful forms had utilitarian, adaptive value. In this sense, his orchid book was to be read as proof of natural selection and adaptation, indeed, as a study of the hardest case (Browne, Charles; Desmond and Moore).
Researchers investigating plant pollination ecologies today engage a set of evolutionary theories that have been modified significantly since Darwin’s elaboration of natural selection in his 1859 Origin of Species. Plant and insect behaviors are now grounded in deterministic models that reduce interactions among species to the actions of “selfish genes” geared to the task of reducing an organism’s energy expenditure while maximizing its reproductive fitness for long-term species survival (see Dawkins, for example). Such neo-Darwinian accounts are endemic to the burgeoning field known as “chemical ecology” (see Dicke and Takken, for example). Researchers in this field home in on the chemical determinants that shape ecological relations, including the pheromones and other signaling chemicals that organisms secrete to attract, repel, and communicate with one another. If Darwin described the brilliant range of colors, flexible forms, sensual textures, and sweet nectars that attracted pollinators to orchid flowers, today chemical ecologists approach plants with attentions and instruments attuned to the plumes of volatile chemical attractants that plants synthesize and release into the atmosphere.
Neo-Darwinian logics are particularly pronounced in studies currently being conducted on Ophrys orchids (see, for example, Vereecken and Scheistl; and Vereecken et al.). Many of the numerous species that comprise the Ophrys genus have the remarkable ability to lure pollinators in spite of the fact that they do not offer the insects a nectar “reward.” Chemical ecologists have found that Ophrys species can attract their pollinators selectively by exhaling volatile compounds that mimic the sex pheromones of their insect pollinators. These volatile plumes can elicit “typical” sexual behavior in male insects: for example, scientists have observed excited male bees swarm around flowers, expose their genitalia before landing, and engage in “precopulatory movements” as they feverishly try to mate with the flowers (Nilsson 257). In so doing, the bees “inadvertently” participate in orchid fertilization.