Monday, 20 April 2015

Males Are Here To Stay: Sex Enhances Egg Production And Colony Fitness

To us humans, it seems extremely unnatural that other animals can reproduce without having sex. Yet with the passing of time, evolution has endowed females of several species of amphibians, insects, reptiles and fish the ability to asexually produce offsprings without "help" from males.

Now, researchers at the Okinawa Institute of Science and Technology Graduate University (OIST) say that in such animals, fertilization still has an important role, ensuring the survival of the maximum number of healthy offsprings. Their research appears online in The Science of Nature.

Generally, most species capable of parthenogenesis (asexual reproduction) use it to increase their numbers faster in harsh environments when females can't find males. Asexual reproduction also comes handy when many females but few males enter a new habitat.

Scientists speculate that this ability originally arose in many species, either due to conflict between the sexes or to ensure survival when mates were scarce. Some of these species now consist entirely of females.

The OIST Ecology and Evolution Unit has looked at the early evolutionary transition from sexual reproduction to clonal reproduction by studying a special case: the Little Fire Ant. Also known as the electric ant (Wasmannia auropunctata), it is a small (approx 1.5 mm long), light to golden brown social ant native to Central and South America, now spread to parts of Africa (including Gabon and Cameroon), North America, Puerto Rico, Israel, and six Pacific Island groups plus north-eastern Australia.

Little fire ant bities a human
Little fire ant biting a human
By Plegadis (Own work) [Public domain]

W.auropunctata is a species in which certain populations reproduce sexually and others clonally, yet colonies of both types still have males.

As is the case of other ants, the males of this species fertilize queens to produce a worker class where all individuals are sterile, and accept genetic contributions from both parents. But here is where the twist comes.

In W.auropunctata fertile males hatch with no genetic contribution from the queen laying the egg, and new queens hatch without genetic contribution from the father. But why do males still exist, and mating still takes place in a species where the male and female genetic information stays separate and queens also have the ability to clonally produce both queens and workers?

To answer this, the OIST researchers studied colonies from both sexually and clonally reproducing populations. They discovered that inseminated queens had almost a 100 percent success rate in terms of how many of their eggs hatched, whereas in the case of queens that remained virgin, from both clonally and sexually reproducing populations, the majority of the eggs did not make it past early stages of embryo development. Furethermore, queens that haid sex laid eggs faster than the virgin ones.

 little fire ant worker foraging for food on a leaf's surface
Little fire ant worker foraging for food


The study strongly suggests that in the Little Fire Ant case the battle of sexes is unlikely. Mating with males enables the queen to produce more healthy offsprings than by cloning itself. Sex also increases a queen's fitness as indicated by the enhanced egg laying and hatching success rates and as a result, the colony's fitness.

"In case of the whiptail lizard in the New Mexican desert which consists only of females, a type of pseudo-copulation still takes place before eggs start developing, suggesting evolution places certain checks on completely eliminating sex and sexual behavior," said Prof. Alexander Mikheyev, head of OIST's Ecology and Evolution Unit, the paper's co-author.

The mechanisms by which evolution prevents sex from being completely eliminated still remain largely mysterious. But what is certain is that even though some species can bypass the need for sex to deal with challenging conditions, an evolutionary constraint seems to be wiring the females in these species to still expect sexual stimulus. Without it, their reproductive systems just don't perform as well.

References
- Miyakawa MO, & Mikheyev AS (2015). Males are here to stay: fertilization enhances viable egg production by clonal queens of the little fire ant (Wasmannia auropunctata). Die Naturwissenschaften, 102 (3-4) PMID: 25801787

Friday, 17 April 2015

Armored Sea Robin



This weird looking creature is an Armored sea robin (Peristedion sp.). Both photos were taken at 600 meters (1,970 feet) deep by NOAA’s Deep Discoverer remotely operated vehicle.

Video: Rare Sperm Whale Encounter In The Gulf Of Mexico

The team of E/V Nautilus* uploaded three days ago an amazing video from an encounter they had with a sperm whale. The encounter took place at 598 meters below the Gulf of Mexico, off the coast of Louisiana. The magnificent creature circled Hercules several times and gave the cameras a chance to capture it in all its glory. According to the scientists, encounters between sperm whales and ROVs are extremely rare.

Enjoy:



* The Exporation Vessel (E/V) Nautilus is a 64-meter research vessel with one simple goal. To explore the world's oceans! With the help of Hercules, Argus, Diana and other remotely operated vehicles, the crew continuously makes new contributions on biology, geology, archeology, and other sciences. Visit http://www.nautiluslive.org for LIVE video from the ocean floor!

Wednesday, 15 April 2015

Gerenuk: The Giraffe-necked antelope

A female gerenuk, notice the long neck and small head
Gerenuk
Credit
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Family: Bovidae
Subfamily: Antilopinae
Genus: Litocranius
Species: Litocranius walleri
Conservation Status: Near Threatened
Common Name(s): Gerenuk, Waller's gazelle, giraffe-necked antelope

Meet the gerenuk, a long-necked species of antelope and the sole member of the genus Litocranius. The species occurs in dry thorn shrubland and desert in the Horn of Africa (or Somali Peninsula) and the African Great Lakes region.

The name gerenuk comes from the Somalian word "Garanuug" which not-surprisingly translates to "giraffe-necked".



Description
From head to tail, gerenuks are about 150 cm (59 in) long. Males are slightly taller, at 89 - 105 cm (35–41 in) tall whereas females are usually 80 - 100 cm (31–39 in) tall. Male generuks are also heavier than females, with an average weight of 45 kg (99 lb), while females have an average weight of about 30 kg (66 lb).

The head is small compared to the body, but the eyes and ears are proportionately large. Males come with a set of horns and have a generally more muscular neck than females. Both sexes have ruddy brown coats with a paler underbelly. They have short, black tipped tails.

The species most distinctive trait is the remarkably long and skinny neck which can be elongated even further when required, e.g for activities like feeding off a tall tree.

The legs are long and slender and help the animal to achieve high speeds, something useful when trying to avoid predators. However, the extreme length of their legs makes them prone to fractures and other injuries.

Males reach sexual maturity at 1.5 years of age and females at around one year.

Individuals have been reported to live 13 years or more in captivity and at least eight years in the wild.

Male gerenuk in classical feeding pose
Male Gerenuk in Buffalo Springs/Samburu N.P., Kenya
Credit

Subspecies
There are two recognized subspecies:
  • Southern gerenuk, Litocranius walleri walleri 
  • Northern gerenuk, Litocranius walleri sclateri 

Video showing a southern Gerenuk

Diet
Gerenuks are well adapted for finding food in their arid habitats. Their long necks and legs in combination with the ability to stand on their hind legs allows them to obtain tree leaves that are out of reach for most other antelope species. This permits them to be selective in what they eat and to be efficient browsers of herbaceous plants.

Research has shown that they consume at least 80 different species of plants.

Two gerenuks feeding of a tree
Gerenuks feeding of a tree in the Samburu National Park - Kenya
Credit


Behavior & Reproduction
They prefer to live in small groups, some made up entirely of females and their offspring and some exclusively by males. Often, a solitary male will hold a specific territory where female groups may wander over a range of 1 - 2 square miles, roaming through several male territories.

Reproduction occurs throughout the year and the gestation period lasts about seven months. Females give birth to usually one young which has a weight of about 3 kg (6.6 lb) at birth.

Gerenuk females breed every one or two years, depending on the sex of their previous year's offspring. This is because male youngs depend on their mothers for longer than females do.


Gerenuk at Oregon Zoo

Conservation Status & Threats
The species is currently (2015) classified by the IUCN as Near Threatened (NT) and has already been eliminated from certain parts of its historical range in East Africa. Fortunately, it remains a widespread and relatively common antelope. Main threats, outside of the protected areas, include habitat loss and degradation, due to the expansion of agriculture, and hunting.

Which zoos have them?
The animal is exhibited in many zoos throughtout the world. Some zoos in the U.S. featuring this weird animal are:
  • Los Angeles Zoo
  • Saint Louis Zoological Park (United States)
  • San Diego Zoo
  • Oregon Zoo

Just do a google search to see if a zoo or park near you has these beautiful animals for exhibition!

Gerenuk at Tsavo East National Park in eastern Kenya

Other Interesting Facts about Gerenuks
- The gerenuk is believed to be independent of free water, obtaining all the moisture it needs through its diet.
- Offsprings were produced through artificial insemination for the first time in 2010 at White Oak Conservation in Yulee, Florida.
- Gerenuks use several vocalizations, including a buzzing sound when alarmed, a whistle when annoyed and a loud bleat when in extreme danger.

Tuesday, 14 April 2015

Dogs Struggling With Nonexistent Doors

Plain stupid or well trained? What's ever the case, the result is the same. These three dogs will bring a smile to your face. Enjoy!







Monday, 13 April 2015

7 Transparent Animals That Will Blow Your Mind

The world is full of weird and bizarre creatures that come in all kinds of colours and patterns. But some of them are different..instead of colors they use transparency to embed with the surrounding environment, usually in an effort to avoid predation.

Here is a pick of 7 transparent animals that will blow out your mind!

1. Glass Frogs

glass frog, Cochranella pulverata species
Glass Frog of the Cochranella pulverata species
Credit

Glass frogs are small frogs of the family Centrolenidae While the general background coloration of most of them is lime green, the abdominal skin of some members of the family is translucent. As a result, several organs including the heart, liver, and gastrointestinal tract, are visible through their skin, earning them the glassfrog nickname.

2. Glasswing butterfly (Greta oto)

Greta otto, the butterfly with the transparent wings
Glasswing Butterfly

While many butterflies are popular for their bright colors and unique patterns, the glasswing butterfly (Greta oto) is best known for its almost completely transparent wings. The spanish name for the species is "espejitos", which translates to "little mirrors".

3. Pacific barreleye

Pacific barreleye, one of the weirdest fish in the world
Pacific barrel-eye

Also known as the Spook Fish, the pacific barreleye fish (Macropinna microstoma) is one the weirdest looking creatures lurking deep in the ocean. The species is named after its eyes which are literally shaped like small barrels. As you can see in the photo, the species' most distinctive trait is the transparent, fluid-filled dome on its head.


4. Crocodile Icefish

transparent larva of Crocodile Icefish
Crocodile Icefish Larva

These ghostly Antarctic predators from the Channichthyidae family are largely translucent due to their colorless blood that contains no hemoglobin. Most species have no red blood cells and when present they are very rare and defunct. Also known as white-blooded fish.


5. The transparent snail (Zospeum tholussum)

Zospeum tholussum, the semi-transparent snail
Zospeum tholussum
The newly discovered Z. tholussum is a cave-dwelling species of air-breathing land snails and has a semi-transparent shell which is beautifully shaped like a dome. The species is extremely small, with a shell height of less than 2 mm. It was discovered at depths of 743 to 1,392 m (2,438 to 4,567 ft) in the Lukina jama–Trojama cave system in Croatia in 2010 during a caving expedition.

6. Glass Squids

Transparent glass squid (Cranchiidae sp)
Glass Squid, Cranchiidae sp
There are about 60 different species of glass squids, all in the family Cranchiidae. The common name, glass squid, derives from the transparent nature of most species which provides camouflage. Many glass squids are also bioluminescent and possess light organs on the undersides of their eyes, used to cancel their shadows. 

7. Golden tortoise beetle

The beautiful and partially transparent Golden tortoise beetle
Golden tortoise beetle

The beautiful golden tortoise beetle (Charidotella sexpunctata) may not be completely transparent, however it does feature a carapace that is nearly invisible. Adults are 5 to 7 mm long and have a variable color, ranging from orange to gold and often metallic, hence the nickname "goldbug". The external margins are expanded and lack pigmentation, becoming nearly transparent

Saturday, 11 April 2015

Cute Video: Puppy loves kitty!

One of the cutest videos you have ever seen, this adorable cocker spaniel puppy really loves this cat!