Feather-horned Beetle (male) - Rhipicera femorata

Rhipicera femorata (Coleoptera - Rhipiceridae) is an uncommon beetle, in fact, most members of the small family Rhipiceridae are extremely rare and consequently little or nothing is known about their biology and habits. The adults are easily recognized by the large, fan-shaped antennae composed of many long segments, and the presence of membranous lobes on the tarsal segments.

This species occurs in Australia, inhabiting mostly sandy swamplands and immediate environs, with sedges, grasses and other swampy land trees.

Larval Rhipiceridae are ectoparasites of cicadas in North America, and it is probable that R. femorata is also parasite of cicadas and that the adult beetles emerge from their hosts in the ground when warmer weather conditions trigger their emergence from the ground surface.

References: [1] - [2]

Photo credit: ©Kerry Vaneeden | Locality: Perth, Western Australia, Australia (2014)


Lately I have been the mite whisperer!  I had four cases of Demodex last week and two cases of Sarcoptes!  Sarcoptic mange, caused by the little creature in the first photo, is transmissable to humans and other animals.  It causes a self-limiting infection in people with itching and redness, but in dogs, the infestation can be severe and excruciating.  Demodectic mange is not uncommon in puppies, who are still developing their immune system; Demodex, unlike Sarcoptes, is a normal inhabitant of most mammals, including people.  Demodex mites only become a problem when the immune system is suppressed; if that’s the case, they can infest the whole body and also cause pain and itchiness.  Both types of mange leave the pets open to secondary bacterial invasion.

Sarcoptes can be fairly easily treated with Revolution topically.  Demodex, however, is a huge pain in the butt to treat and requires time-consuming and dangerous dips, or oral ivermectin, which can cause nasty side effects.  I hate Demodex!


The riddle of zebras’ stripes

Why zebras have black and white stripes is a question that has intrigued scientists and spectators for centuries. A research team led by UC Davis, has now examined this riddle (in a very systematic way).

Many hypotheses for zebra stripes have been proposed since Alfred Russel Wallace and Charles Darwin debated the problem 120 years ago. These include:

  • A form of camouflage
  • Disrupting predatory attack by visually confusing carnivores
  • A mechanism of heat management
  • Having a social function
  • Avoiding ectoparasite attack, such as from biting flies

After analyzing the five hypotheses, the scientists ruled out all but one: avoiding blood-sucking flies. The scientists found that biting flies (such as horseflies and tsetse flies) are the evolutionary driver for zebra stripes.

Why would zebras evolve to have stripes whereas other hooved mammals did not? The study found that, unlike other African hooved mammals living in the same areas as zebras, zebra hair is shorter than the mouthpart length of biting flies, so zebras may be particularly susceptible to annoyance by biting flies.

Yet in science, one solved riddle begets another: Why do biting flies avoid striped surfaces?

[images via headlikeanorange and gif-book]

The flat disc on the top of a remora is actually a modified dorsal fin! They use them to suction onto marlin or other large sailfish, cruising around the ocean and eating their host’s dead skin and ectoparasites. Yum! Check out this and more tonight and tomorrow during #MembersNight65! – 📷 Marlin sucker (Remora osteochir).

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Scientists solve the riddle of zebras’ stripes

A research team led by the University of California, Davis, has now examined why zebras have black and white stripes. Their answer is published April 1 in the online journal Nature Communications.

The scientists found that biting flies, including horseflies and tsetse flies, are the evolutionary driver for zebra’s stripes. Experimental work had previously shown that such flies tend to avoid black-and-white striped surfaces, but many other hypotheses for zebra stripes have been proposed since Alfred Russel Wallace and Charles Darwin debated the problem 120 years ago. These include:

  1. A form of camouflage
  2. Disrupting predatory attack by visually confusing carnivores
  3. A mechanism of heat management
  4. Having a social function
  5. Avoiding ectoparasite attack, such as from biting flies

The team mapped the geographic distributions of the seven different species of zebras, horses and asses, and of their subspecies, noting the thickness, locations, and intensity of their stripes on several parts of their bodies. Their next step was to compare these animals’ geographic ranges with different variables, including woodland areas, ranges of large predators, temperature, and the geographic distribution of glossinid (tsetse flies) and tabanid (horseflies) biting flies. They then examined where the striped animals and these variables overlapped.

After analyzing the five hypotheses, the scientists ruled out all but one: avoiding blood-sucking flies.

“I was amazed by our results,” said lead author Tim Caro, a UC Davis professor of wildlife biology. “Again and again, there was greater striping on areas of the body in those parts of the world where there was more annoyance from biting flies.”

Caption: UC Davis scientists have learned why zebras, like these plains zebras in Katavi National Park, Tanzania, have stripes. Credit: Tim Caro/UC Davis


The Anting Behavior of the White-bearded Manakin 

The White-bearded Manakin, Manacus manacus (Passeriformes - Pipridae) is a South American bird well known for forming very noisy leks (arenas where males compete to attract females and secure matings). The male is mainly black and white but the female is olive tones.

According to a recently published article, males of this species exhibit the so-called Anting Behavior, defined as a bird holding an ant and rubbing it in parts of the body, discharging toxic and distasteful substances before ingesting or discarding the ant. So, males of Manacus manacus use up to seven Solenopsis sp. ants, and they rub each small ant from 4 to 31 times on undertail feathers until the ants are degraded (ants are not eaten). 

Formic acid found in ants acts smoothing skin irritation and as an insecticide, bactericidal, and fungicide on bird feathers. Thus, plumage maintenance and prevention of ectoparasites are some of the functions attributed to anting behavior.

It is supposed that seeds discarded by males (they are frugivorous) on their individual display courts (leks) attract herbivorous ants that are used for anting as a way to maintain feathers and fitness. It is hypothesized that anting in White-bearded Manakin may increase the probability of males to attract females to their leks.

References: [1] - [2] - [3]

Photo credit: ©Félix uribe | Locality: San Rafael, Antioquia, Colombia, 2012 | [Top] - [Bottom]

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The six winged insect, Palaeodictyoptera (1877)

Phylum : Arthropoda
Class : Insecta
Order : Palaeodictyopteroidea
Genus : Paleodictyoptera

  • Late Carboniferous/late Permian (318 - 251 Ma)
  • 40 cm long (size)
  • Europe (map)

They were characterised by beak-like mouthparts, similarity between fore- and hind wings, and an additional pair of winglets (large paranotal lobes) on the prothorax, in front of the first pair of wings. Although the paranota are technically not wings, the Palaeodictyoptera are whimsically called “six-winged insects”. The actual wings are often boldly marked, the colour patterns evident even in fossils.

The mouthparts were elongated, and included sharp piercing stylets, and possibly a sucking pump-like organ. Unlike modern sucking insects, such as the Hemipterans, the mouthparts were held vertically below the head, or projected forwards. They probably used these organs to suck juices from plants, although some may have been ectoparasites, or predators.

Some types attained huge size. For example, Mazothairos had a wingspan of about 55 centimetres. Another distinctive feature was the presence of unusually long cerci, about twice the length of the abdomen.

The Palaeodictyoptera are a paraphyletic assemblage of basal palaeodictyopteroidean insects, rather than a clade, because they gave rise to other insect orders. They range in time from the Middle Carboniferous (late Serpukhovian or early Bashkirian in age) to the late Permian.

Tent-making bats are discerning builders

At least 14 species of neotropical bats in the family Phyllostomidae have been reported to modify leaves of plants to construct tents as roost. Each species of tent-making bat has one or more distinctive styles of tent construction and may utilize one or more species of plant.

Several studies suggest that tents provide bat with shelter to hide from terrestrial and arboreal predators, and also provide them with refuge from rain, wind, and high light intensities. 

Roosting in tents is believed to confer protection from potential predator, because most plants utilized for tents have very long petioles and would be easily moved by a terrestrial predator approaching from the ground or a snake moving up the petiole. Moreover, since tent roosts are relatively open, they provide bats with a clear view of potential predator approaching and the possibility to escape.

Tent Roosting may also allow some species of bats to frequently change roosts and thus avoid high rates of ectoparasite infection that are characteristic of bats roosting in more permanent sites, such as caves, hollow trees, and buildings.

It also has been hypothesized that a selective force in the evolution of bat tent construction is a polygenous mating system in which males construct tents in order to attract females.

Anyway, it’s a fact that tent-making bats choose the leaves to construct their tents, selecting leaves with specific characteristics including height and angle of the stem. Specifically, the Thomas’s fruit-eating batArtibeus watsoni (pictured), utilizes about 20 different plant species for tent construction, half of which are palms, having special preference for the Asterogyne martiana (Arecaceae) palm, and avoiding leaves higher than 5m.

Reference: [1]

Photo credit: ©Peter Nijenhuis | Locality: Rainforest around Rara Avis, Sarapiquí, Heredia, Costa Rica.

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Roman Sanitation Practices May Have Spread Parasites

“CAMBRIDGE, ENGLAND—Archaeological evidence suggests that Europeans conquered by the Roman Empire experienced a gradual increase in intestinal parasites and ectoparasites, such as lice and fleas, in spite of Roman sanitation technologies. “Modern research has shown that toilets, clean drinking water and removing feces from the streets all decrease risk of infectious disease and parasites. So we might expect the prevalence of fecal oral parasites such as whipworm and roundworm to drop in Roman times—yet we find a gradual increase. 

The question is why?” Piers Mitchell of Cambridge University asked in a press release. He thinks that the warm communal waters of the bathhouses, which may have been changed infrequently, could have contributed to the spread of parasitic worms. The Romans also used human excrement from the public latrines as a crop fertilizer. And the widespread use of garum, a condiment made from uncooked, fermented fish parts, may have contributed to the increase of fish tapeworm eggs during the Roman period. “It seems likely that while Roman sanitation may not have made people any healthier, they would probably have smelt better,” Mitchell said.“
Darwin’s finches treat their feathers with a natural repellent
(open access article)

Darwin’s finches are highly innovative. Recently we recorded for the first time a behavioural innovation in Darwin’s finches outside the foraging context: individuals of four species rubbed leaves of the endemic tree Psidium galapageium on their feathers. We hypothesised that this behaviour serves to repel ectoparasites and tested the repellency of P. galapageium leaf extracts against parasites that negatively affect the fitness of Darwin’s finches, namely mosquitoes and the invasive hematophagous fly Philornis downsi. Mosquitoes transmit pathogens which have recently been introduced by humans and the larvae of the fly suck blood from nestlings and incubating females. Our experimental evidence demonstrates that P. galapageium leaf extracts repel both mosquitoes and adult P. downsi and also inhibit the growth of P. downsi larvae. It is therefore possible that finches use this plant to repel ectopoarasites.

(image source)