Red Palm Weevil

Actually a very beautiful animal, this red palm weevil (Rhynchophorus ferrugineus), is widely found in southern Asia and Melanesia, where it feeds on a broad range of palms including coconut, sago, date, and oil palms. It is a serious pest of palms, particularly coconut. For example in Tamil Nadu, India, yield losses of 10-25% have been recorded in coconut plantations. It is the most important pest of the date palm (Phoenix dactylifera) in the world.

Red Palm Weevil

I found this weevil in my garden below a coconut tree . I picked it up using a stick which was held in my left hand. I photographed with camera stabilized in my right hand. I had to balance a quite heavy setup of Canon EOS 5D mark II with Canon EF 100mm f/2.8L Macro IS. Light was provided by Ray Flash Adapter fitted on Canon Speedlite 580EX II. The grey wall you see at the back is in fact the white wall of my house which was around a feet away. Since the light dropped off rapidly from the flash it gave a nice grey background.

Turn around

On these Photos you might recognize, that mites are transported on the legs of this weevil. This process is called phoresy, which means one animal attaching to another for transportation only. Examples of which are mites on insects (such as beetles, flies, or bees), pseudoscorpions on mammals or beetles, and millipedes on birds. Phoresy can be either obligate or facultative (induced by environmental conditions) commensalism.

Mighty Mites

Since the 1980s the Weevil has rapidly expanded its geographical range westwards from Southern Asia. It reached Saudi Arabia and the United Arab Emirates in about 1985, spreading throughout the Middle East and into Egypt. In 1994 it was detected in Spain and in 1999 in Israel, Jordan and the Palestinian Authority Territories. It has since spread to the Balearic Islands (2006), Canary Islands (2005), Cyprus (2006), France (2006), Greece (2006), Italy (2004) and Turkey (2007). The two main palm species of concern in the Mediterranean region are date palm and Canary Island date palm (P. canariensis), the main crop and ornamental species, but it also attacks several other ornamental palms that are regularly imported into Britain, such as chusan palm (Trachycarpus fortunei).

Planning For Take off

Rhynchophorus palm weevils are large insects (usually greater than 25 mm long) which belong to the Rhynchophorinae, a subfamily within the Curculionidae. Adults are large, being up to 42 mm and 16 mm wide, with a long rostrum, characteristic for the weevils. They are reddish-brown in colour with variable dark markings on the pronotum. All life stages may be spent inside the host palm. Each adult female deposits between 200 to 300 eggs in separate holes or cavities on the host plant. Eggs are whitish-yellow, smooth, shiny, cylindrical with rounded ends, slightly narrower at the anterior end, and about 3 mm long and 1 mm wide. These hatch in two to five days, and larvae bore into the interior of the palms, feeding on the soft succulent tissues, discarding all fibrous material. Larvae are legless, with a creamy-white body and brown hard head capsule, and grow up to 50 mm in length. The larval period varies from one to three months. Pupation occurs in an elongate oval, cylindrical cocoon made of fibrous strands, about 40 mm in length. Adult weevils emerge 2-3 weeks after pupation. Thus the life cycle is completed in about 4 months.

Wing Open

Natural and uncultivated areas within southern India, R. ferrugineus is normally a rare and local insect. However, the commercialization of coconut and oil palm growing within tropical Asia, particularly the development of plantation monocultures, has facilitated the range expansion of this insect. Equally the commercialization of date palm growing in the Middle East has created ideal conditions for the rapid spread of the red palm weevil between countries in that region.

Early symptoms of attack are distinctive but hard to see: egg laying notches; cocoons inserted into the base of the palms; an eccentric growing crown; holes at the base of cut palms; symptoms resembling those caused by lack of water such as wilting, desiccation and necrosis of the foliage tunnelling within the stems and trunk. Larvae and adults destroy the interior of the palm tree, often without the plant showing signs of deterioration unless damage is severe. Hollowing out of the trunk reduces its mechanical resistance, making the plant susceptible to collapse and a danger to the public. In most cases, attack on Phoenix and other palms leads to the death of trees whatever their size. Visual examination allows detection of symptoms but cannot determine if there are larvae and adults present inside the trunk. Pheromone traps, acoustic detection or infrared systems can be used to detect this pest.

Ready.... Steady....GO

Economic Importance and Damage Rhynchophorus ferrugineus is a major economic pest of coconut palm, date palm, oil palm and sago palm. It also attacks a wide range of ornamental palms. Severely attacked plants exhibit a total loss of foliage and rotting of the trunk, which eventually results in the death of the tree. Control Measures The availability of effective insecticide treatments against R. ferrugineus are limited. There are several insecticidal treatments that are effective when applied to the soil before planting, but these may be of little/no use as the pest is most likely to be introduced on imported (planted) trees.

Destruction is thus likely to be the only successful eradication measure available. Research into acoustic methods of detection of R. ferrugineus is ongoing, as is research into its control using waveguide (microwave) irradiation. Entomopathogenic nematodes (Steinernema carpocapsae and Heterorhabditis spp.) may also be effective in controlling R. ferrugineus. Considerable research has gone into the study of these biocontrol agents, but with mixed results. Substantial research has also been carried out into the effectiveness of food baited pheromone traps for the mass trapping of R. ferrugineus, achieving good results on a large scale both in the field and in laboratory tests. The addition of dates to pheromone traps has also been shown to be very effective compared to pheromone alone, in field trials in India.

Black Drongo Frontal View

In the last blog I had talked on the Drongo I was chasing. So here are the photos of that photo session where I was chasing these group of Black Drongo’s for a nice pose . It was cloudy, windy and rainy evening. The weather was nice for photography, but light was insufficient.

Cloud was causing variation in light. Trying to capture near black subject against white background was a challenge. I took my meter reading from a single point metering from the body of the Drongo. As we all know camera meters are stupid and they try to adjust the meter to expose to 18% grey. So my black bird would come as 18% grey(means over exposed). To compensate for that I had to under expose by 1.5 stops to get accurate exposure. Other option is to look for some thing which is neutral like green grass which when you convert to grey scale is close to 18% grey and take reading from there. There is also a possibility of sky getting blown out due to higher brightness. Fortunately cloud helped me here to soften that effect. Therefore when you see somebody dismissing a cloudy, overcast day as bad time for photography, you can instantly judge their level of understanding of lighting and photography .

Black Drongo on a Street Light fixture

Black Drongo (Dicrurus macrocercus) is a very common breeding resident bird, found in open areas, wetlands and near cultivation. This is a glossy black bird with a long deeply forked tail. They are usually found in open forests and similar lightly wooded habitats from southwest Iran through India and Sri Lanka east to southern China and Indonesia.

These are aggressive and fearless birds, 28 cm in length, and will attack much larger species if their nest or young are threatened. There are also some cases of Drongos preying on small birds. They have also been on occasion seen feeding on dead fish.

Squabbling Black Drongos

The Black Drongo has short legs and sits very upright whilst perched prominently, like a shrike. The adult Black Drongo is mainly glossy blue-black, although the wings are duller. The tail is long and deeply forked, and there is a white spot in front of the eye. Young birds are dull dark brown.

It lays three or four eggs are laid in a light cup nest placed in a fork often on the bare outer branches of trees.

It eats insects and other small animals. It will attack much larger species if their nest or young are threatened. There are also some cases of Drongos preying on small birds. They have also been on occasion seen feeding on dead fish.

Black Drongo on a Street Light fixture

The Black Drongo has been introduced to some Pacific islands, where it has thrived and become abundant to the point of threatening and causing the extinction of native and endemic bird species there.

It is said that they imitate the call of the Shikra so as to put mynas to flight and then to steal prey. Similar behavior, using false alarm calls, has been noted in the Fork-tailed Drongo. There are some cases of the Black Drongo preying on small birds, reptiles, or maybe even bats.

Black Drongo Dorsal View

Being common, they have a wide range of local names. The older genus name of Buchanga was derived from the Hindi name of Bhujanga. Other local names include Thampal in Pakistan, Gohalo/Kolaho in Baluchistan, Kalkalachi in Sindhi, Kotwal (=policeman) in Hindi; Finga in Bengali; Phenchu in Assamese: Phenchu; Cheiroi in Manipuri; Kosita/ Kalo koshi in Gujarati; Ghosia in Marathi; Kajalapati in Oriya; Kari kuruvi (=charcoal bird), Erettai valan (=two tail) in Tamil; Passala poli gadu in Telugu; Kaaka tampuratti (=queen of crows) in Malayalam; Kari bhujanga in Kannada and Kauda in Sinhalese.

A superstition in central India is that cattle would lose their horn if a newly fledged bird alighted on it. It is held in reverence in parts of Punjab in the belief that it brought water to Husain ibn Ali, an Islamic prophet.

Blue Tiger Moth - Dysphania palmyra

Even though that evening was drizzling I was trying to photograph Black Drongos (Dicrurus macrocercus) which were busy catching insects during late evening. Light was fading but my new Canon EF 300mm f/2.8L IS lens was able to get many pictures albeit in slower speed. As I came back to my In-laws house I saw this day flying moth which flew and sat on the metal box outside their home.

Even though I was not able to reach the box which was sufficiently high I got my trusty rig of Canon EF 100mm f/2.8L Macro IS USM on Canon EOS 5D mark II fitted with ExpoImaging Ray Flash Adapter on Canon Speedlite 580EXII Flash out to shoot this moth. The metal box where it was sitting was a rusty one. The biggest challenge was to reduce the reflection of the flash from the metal box. The ring flash adapter helped me by diffusing the light evenly to produce a pleasant lighting.

Blue Tiger Moth - Dysphania palmyra

This is a very common moth we see around here. It is also one of the few day flying moths as most moths fly in the dark hours of night. It is called by various names as Blue Tiger moth, Four O’clock Moth, Peacock Jewel moth. This Dysphania palmyra species of moth belongs to the Family Geometridae. The inch worm caterpillar which I posted a year back belong to the same family of moths.

Many Geometrids have slender abdomens and broad wings which are usually held flat with the hindwings visible. As such they appear rather butterfly-like but in most respects they are typical moths: the majority fly at night, they possess a frenulum to link the wings and the antennae of the males are often feathered. They tend to blend in to the background, often with intricate, wavy patterns on their wings. In some species, females have reduced wings and are flightless (e.g. winter moth and fall cankerworm).

Most are of moderate size, about 3 cm across but a range of sizes occur. They have distinctive paired tympanal organs at the base of the abdomen (lacking in flightless females).

Blue Tiger Moth - Dysphania palmyra

The name Geometer (earth-measurer) refers to the means of locomotion of the larvae or caterpillars, which lack most of the prolegs of other Lepidopteran caterpillars. Equipped with appendages at both ends of the body, a caterpillar will clasp with its front legs and draw up the hind end, then clasp with the hind end (prolegs) and reach out for a new front attachment – creating the impression that it is measuring its journey. The caterpillars are accordingly called loopers, spanworms, or inchworms. They tend to be green, grey, or brownish and hide from predators by fading into the background or resembling twigs. Some have humps or filaments (see Filament-bearer image). They are seldom hairy or gregarious. Typically they eat leaves. However, some eat lichen, flowers or pollen. Some, such as the Eupithecia, are even carnivorous.

Blue Tiger Moth - Dysphania palmyra