✵The article records the herb Stiff Silkworm, including its English name, Latin name, Pinyin name, properties and flavor, source (a single insect species, Bombyx mori L.), and a detailed introduction to the biological characteristics, growth habits, and ecological environment of this insect; as well as the morphological features of the herb Stiff Silkworm, its pharmacological actions, medicinal efficacy, and administration guidelines.
Bombyx Batryticatus (Stiff Silkworm)
Pinyin Name: Jiānɡ Cán or Bái Jiānɡ Cán
English Name: Stiff Silkworm or White Silkworm
Latin Name:Bombyx batryticatus Properties and Flavor: Cool, pungent, bitter
Brief Introduction:Bombyx batryticatus is the dried body of the fourth- or fifth-instar larva of Bombyx mori L., which has died and stiffened due to infection by the fungus Beauveria bassiana. It is used (1) to extinguish endogenous wind and relieve convulsions, (2) to resolve phlegm and dissipate nodules—particularly in scrofula—and (3) to dispel exogenous wind in wind-heat patterns, such as sore throat, hoarseness, and urticaria. It is commonly known as Bombyx batryticatus, Stiff Silkworm, or Jiāng Cán.
Source: Classical herbal works define Bombyx batryticatus (Stiff Silkworm) as the dried body of the fourth- or fifth-instar larva of Bombyx mori L., killed and rigidified by Beauveria bassiana infection. Bombyx mori L. is a small insect belonging to the genus Bombyx, family Bombycidae (silkworm moth family), order Lepidoptera. This widely used species is described below:
(1) Bombyx mori L.
Insect Description: Commonly known as Sāng Cán or Jiā Cán É (silkworm moth), it is a silk-producing insect. Both male and female moths are densely covered with white scales. Body length measures 1.6–2.3 cm; wingspan ranges from 3.9–4.3 cm. The forewings are yellowish-white to ash-gray (grayish-white); the apical margin of the forewing is concave posteriorly; transverse lines are slightly darker but inconspicuous; the terminal line and veins (pterostigma) are taupe (dusty gray). The hindwings are paler than the forewings, and the marginal scale hairs (cilia) are slightly longer. The female abdomen is stout and blunt-ended; the male abdomen is narrower and slightly pointed. Its larva—the silkworm—exhibits body coloration ranging from ash-gray (grayish-white) to white; the second and third thoracic segments are slightly enlarged and wrinkled; the eighth abdominal segment bears a caudal horn. It is cultivated across most regions of China.
The mulberry silkworm—also known simply as the silkworm—feeds exclusively on mulberry leaves and spins silk to form cocoons. It is one of the world’s most important economic insects. Originating in China, it was domesticated from ancestral wild silkworms (tussore silkworms) that inhabited mulberry trees in antiquity. It is homologous to the modern wild silkworm Bombyx mandarina, which still feeds on mulberry leaves in China today.
Before pupation, the silkworm larva consumes mulberry leaves and secretes large quantities of silk to construct its cocoon—a vital textile raw material. Silkworms are holometabolous insects, undergoing four distinct developmental stages: egg, larva, pupa, and adult. Morphology and physiology differ markedly among these stages. The egg stage represents embryonic development into the larva; the larval stage is dedicated to feeding and growth; the pupal stage involves metamorphosis from larva to adult; and the adult stage serves reproduction—mating, oviposition, and progeny production. Feeding occurs exclusively during the larval stage; nutrients accumulated then sustain life activities throughout the pupal and adult stages.
Silkworms originated in China and were domesticated from primitive tussore (wild) silkworms inhabiting mulberry trees in ancient times. Their morphology and behavior closely resemble those of today’s Bombyx mandarina, a mulberry-feeding wild relative. Serum precipitation reaction intensities are also identical. Silkworms possess 28 pairs of chromosomes, whereas tussore silkworms exhibit either 27 or 28 pairs. Early humans likely collected wild tussore cocoons from mulberry forests for silk extraction. With the advent of settled communities and increasing empirical knowledge of silk production, sericulture gradually shifted indoors. Through prolonged cultivation and selective breeding, the wild tussore was progressively domesticated into the modern Bombyx mori.
Life Habits: Life Habits: The silkworm is an oligophagous insect that feeds primarily on mulberry leaves, but also consumes leaves of Cudrania triloba, elm, dandelion, and lettuce. Silkworms require essential nutrients—including protein, carbohydrates, lipids, vitamins, inorganic salts, and water. Mulberry leaves are the most suitable natural food for silkworms. After feeding on mulberry leaves, larvae grow rapidly. Under optimal temperature conditions, a silkworm molts approximately once every 6–9 days from hatching to cocoon spinning—a process lasting about 24–32 days—during which it consumes 20–30 grams of fresh mulberry leaves (equivalent to 5–6.2 grams of compound dry matter).
Generally, after four molting cycles (also called “instars”), body weight increases by up to 10,000-fold at peak growth. Cocoon spinning is an innate behavior enabling silkworms to adapt to their environment. Mulberry cocoons are used for silk reeling; silk is a valuable textile raw material with wide-ranging applications in military, electrical, and other industries. Silkworm pupae, moths, and feces (called “silkworm guano”) also have comprehensive uses: they serve as raw materials for chemical and pharmaceutical industries and can be applied as organic fertilizers for plants. The silkworm is a holometabolous insect, undergoing four distinct developmental stages—egg, larva, pupa, and adult—in a single generation. The number of generations occurring naturally per year is termed “univoltine” (one generation), “bivoltine” (two generations), or “multivoltine” (more than two generations). Tropical regions also host year-round, non-diapausing, multivoltine varieties.
The temperature range suitable for development varies across life stages, generally spanning 7–40 °C (44.6–104 °F); however, normal development occurs within the narrower range of 20–30 °C (68–86 °F). The silkworm’s annual adaptability to meteorological conditions is directly reflected in its physiological robustness. Healthy tussah (wild silkworm) individuals produce high-quality cocoons; thus, cocoon quality serves as an indicator of tussah vigor.
Morphological Features: The primary objectives of silkworm cultivation are cocoon and silk production. The silkworm’s life cycle comprises four developmentally distinct stages—egg, larva, pupa, and adult—with marked differences in morphology and physiology.
Larva:The larva has a long, cylindrical shape composed of three parts: the head, the chest, and the abdomen. The head is covered with a taupe, bony shell. The thorax has one pair of legs in each of the three segments. The abdomen has 10 segments, each with four pairs of gastropods and one pair of tail pedis. One pair of valves is located on each side of the first thoracic segment, and one to eight ventral segments are present. Newly hatched larvae are covered with black and brown bristles and are as small as ants. They are known as silkworms. Silkworms feed on mulberry leaves and grow quickly. Their body color gradually turns green and white.
The cuticle of its body must be shed many times. This phenomenon is called exuviae, and it is the result of the eutrophic hormone secreted by the pharyngeal lateral body and the exuviae hormone secreted by the thymus acting together inside the silkworm body. Before ecdysis, the larva stops eating mulberry leaves, spins silk on the silkworm seat, and fixes its body with its gastropod and tail foot. It then becomes motionless and sleeps. Each sleep increases the age limit by one year. The weight and volume increase significantly with age. The number of times it molts is known as "sleepiness," which is genetically controlled but can also be altered by living conditions. Silkworms have three, four, five, etc. sleep cycles. The most commonly used silkworm species in production is the five-sleep, five-year-old silkworm.
By the second or third day of the fifth age, it is possible to differentiate between male and female silkworms based on their characteristics. The female has one pair of milky white dots on the ventral surface of the eighth and ninth ventral segments, respectively. These are called the "stone du's gland." The male has a milky white capsule in the middle of the anterior ventral border of the ninth ventral segment. This is called the "hirschner's gland." At this stage, their body weight increases by about 10,000 times. They then gradually reduce their consumption of mulberry leaves and eventually stop eating altogether. When the front half of their bodies turn transparent, the mature silkworms begin to spin silk knot cocoons. The cocooning process takes about two to three days. The length of the larval stage varies by silkworm species and feeding conditions. Generally, the spring silkworm takes about 24 to 26 days at 24 to 25 °C (75.2 to 77 °F), while the summer and autumn silkworm take about 21 to 23 days at 26 to 28 °C (78.8 to 82.4 °F).
Shell time: 5:00 a.m. to 10:00 a.m. Phototaxis is stronger under yellow, green, and white light. After day 5, the body length no longer increases, ranging from 6 to 8 cm. Two days after reaching 5 days of age, the female silkworm has a pair of milky white or transparent dots on the ventral surface of the eighth and ninth ventral segments. The distinctiveness of these dots varies among individuals. The female is usually larger than the male. They spin cocoons in 1-2 days and mostly spin silk in the dark.
The suitable temperature is 22-28°C (71.6-82.4°F), with an optimum temperature of 23.8-25°C (74.84-77°F). From incubation to spinning the cocoon generally takes 24-30 days in the spring and 20-24 days in the summer and fall.
Pupa: the pupa stage is when the mature silkworm spins its cocoon. The body becomes slightly fusiform (spindle-shaped) and motionless. This stage is called the latent pupa (prepupa). The chrysalis period occurs when the dermis separates from the old larval epidermis and forms the pupal epidermis, a process that takes about two days. Pupal molting is the result of a molting hormone. The newly molted pupa is spindle-shaped and cream white, later turning dark brown. The pupa's body is divided into three parts: the head, the thorax, and the abdomen. The abdomen of the female pupa is large and obtuse at the end. The male pupa has a small terminal apex with a small brown dot on the ventral surface of the ninth ventral segment. The pupa weighs 1.5 to 2.5 grams. The destruction of larval tissues, the formation of adult tissues, the development of germ cells, and other physiological processes occur in the pupa. After the pupal stage, adult development is completed in about 14 days. At this time, the brain nerve secretion cells synthesize and store the eclosion hormone in the pharyngeal side of the body. Due to light stimulation, the hormone is secreted into the blood. In about 40 minutes, the pupa eclosions.
The optimal temperature for silkworm chrysalises is between 23.9 and 24.4 °C (75.02 and 75.92 °F), with an ideal range of 22.8 to 26.7 °C (73.04 and 80.06 °F). The maximum temperature should not exceed 28 °C (82.4 °F). Pupation takes one to two days. The pupal stage takes 15 to 18 days. Opening the cocoon takes 10 to 11 days. When the pupa was protected at 28 °C (82.4 °F) for 24 hours on the second day, non-diapause eggs were easily produced.
Silkworm pupae should be refrigerated three days after transformation. The appropriate refrigeration temperature is between 2.5 and 10 °C (36.5 and 50 °F), with an optimal temperature of 5 and 7.5 °C (41 and 45.5 °F). The minimum temperature for development is 10 °C (50 °F).
The female pupa has a hypertrophic abdomen and a longitudinal line on the midline of the ventral surface of the eighth ventral segment. The male pupa has a small point at the midline junction of the eighth and ninth ventral segments.
Adult: After emerging from the cocoon, the adult moth secretes an alkaline intestinal liquid to wet and loosen the silk layer at the head end of the cocoon. The moth then uses its chest and feet to open the cocoon. The wings are soft and folded at first, but later the moth's body dries out and the wings spread. Its entire body is covered with white scales. There is a pair of compound eyes and a pair of pectinate antennae with a sense of touch and smell on both sides of the head. There is one pair of pedipalps on the ventral surface of the front, middle, and back of the thorax, and one pair of wings on the back of the middle and back of the thorax. The female moth has seven abdominal segments, while the male moth has eight. The male moth's external genitalia change from the ninth and tenth ventral segments of the larva, while the female moth's change from the eighth, ninth, and tenth ventral segments. During mating, the female moth extends her ovipositor and releases sex pheromones (silkworm alcohol and silkworm aldehyde) from her alluring gland to attract the male moth. Fertilized eggs can be produced within one and a half to two hours after mating. A female moth lays approximately 400 to 700 eggs, most of which are laid on the first day and finished by the third day. Adult moths do not eat after mating and live about 10 days before dying of natural causes. Moths usually mate for two hours between 5 and 10 o'clock. After mating, they spawn for three to four hours and die five to twelve days later. The optimal temperature range is 21-27°C (69.8-80.6°F).
Egg: The egg is oval and slightly flattened. It is about 1.3 mm long, 1.1-1.2 mm wide, and 0.5-0.6 mm thick. One end is slightly blunt and the other end is slightly pointed. The tip of the egg has a hole that serves as a fertilization channel. Egg size varies with silkworm species, feeding conditions, and pupal temperature. Eggs generally weigh between 500 and 600 micrograms. When first laid, the eggs are faint yellow with a raised surface. Due to the evaporation of water and consumption of nutrients inside the eggs, a depression forms in the middle of the egg surface called the egg vortex. A normal egg is oval, while a dead egg is triangular. The surface of the eggshell is uneven with a polygonal texture and countless needle-like breathing pores. The egg's contents are the yolk membrane, serous membrane, yolk, and embryo. The yolk membrane, which is a layer of transparent, non-cellular film, is close to the undersurface of the eggshell. The serous membrane, which is a layer of large, flat, polygonal cells, is on the inside. The yolk provides nutrients for embryo development. The embryo develops gradually by ingesting nutrients from the yolk inside the egg, with its head toward the foramen.
There are two types of silkworm eggs: diapause and non-diapause. After the female silkworm lays non-diapause eggs, the embryo develops continuously and forms a silkworm that hatches in about 10 days. The embryo of a diapause egg develops to a certain degree and enters the diapause period. It hibernates through the winter and hatches in the spring when it is warm. Whether silkworm eggs diapause depends on whether the subpharyngeal ganglion of the pupa can secrete the diapause hormone. Diapause is also assisted by a hormone in the lateral body of the heart. When diapause eggs enter the diapause stage, pigment granules form and are deposited in the dark brown serous membrane cells. Non-diapause oocytes do not form pigment and remain pale yellow.
The optimal incubation temperature for silkworm eggs is 22-25.5°C (71.6-77.9°F), and it takes 9-11 days. The suitable incubation temperature is 20-30°C (68-86°F). After spring, it takes 2-9 days. In spring, when the natural temperature is above 12 °C (53.6 °F), it takes 22 to 27 days. It takes 30 to 100 days for the diapause eggs to hatch. The appropriate temperature during the diapause period is 25 to 30 °C (77 to 86 °F). The temperature should not exceed 35 °C (95 °F), and the humidity should be maintained several days before hatching. The temperature of the eggs should not exceed 30 °C (86 °F) within three hours after laying to avoid affecting the fertilization rate. If the temperature exceeds 30 °C (86 °F) within one day after laying, the eggs are more likely to become non-diapause eggs.
Characteristics of the Herb: The herb is slightly cylindrical, mostly bent and shriveled, 2–5 cm long, and 0.5–0.7 cm in diameter. The surface is sallow (grayish-yellow), covered with white powdery and creamy aerial hyphae and conidiospores. The head is circular (roundish), with 8 pairs of pedicels; somites are conspicuous, and the tail is slightly dichotomous. The texture of the herb is hard and brittle, easy to break; the fracture surface is flat, the outer layer is white and mealy, and the center is bright brown or coracinus (glossy black), commonly known as “glue-mouth mirror”. It contains four silk gland rings internally, which appear as bright rings. The herb has a slightly fishy odor and tastes slightly salty.
Pharmacological Actions: (1) hypnotic and anticonvulsant effects; (2) anticoagulant effect; (3) mild inhibition of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and other bacteria; (4) hypoglycemic effect; (5) antitumor activity.
Medicinal Efficacy: Calming endogenous wind and relieving convulsions, dispelling pathogenic wind and alleviating pain, resolving phlegm and dissipating nodules, detoxifying and relieving sore throat. It is indicated for liver-wind-phlegm syndrome, fright-induced epilepsy and convulsions, wind-related headache, acute infantile convulsions, tetanus, apoplexy and facial paralysis, stroke with aphonia (apoplexy and loss of voice), headache due to wind-heat invasion, migraine (migraine headache), and generalized headache; red eyes and pharyngalgia (acute conjunctivitis and sore throat); sore throat (acute pharyngitis), pharyngitis (throat obstruction), swelling and pain in the throat; urticaria and pruritus (urticarial rash and itching); acute suppurative parotitis (suppurative inflammation of the parotid gland); mumps (an acute contagious viral disease characterized by fever and swelling of the parotid glands); scrofula (lymph node tuberculosis); sores and toxins; erysipelas (“St. Anthony’s fire”); mastitis (mastadenitis); etc.
Administration of Bombyx Batryticatus (Jiānɡ Cán):
Reference:
Administration Guide for Bombyx Batryticatus (Jiānɡ Cán)
TCM Books:
(1) Internally: 5–10 grams; (2) Internally: water decoction, 1.5–3 qian (≈4.5–9 grams), or prepared as pills or powder; external use: apply finely ground herb powder topically—sprinkle or paste; (3) Internally: water decoction, 3–10 grams; finely ground herb powder, 1–3 grams; or prepared as pills or powder. External use: appropriate amount—wash with herbal decoction; or apply finely ground herb powder topically—sprinkle or paste.
✵The article records the herb Stiff Silkworm, including its English name, Latin name, Pinyin name, properties and flavor, source (a single insect species, Bombyx mori L.), and a detailed introduction to the biological characteristics, growth habits, and ecological environment of this insect; as well as the morphological features of the herb Stiff Silkworm, its pharmacological actions, medicinal efficacy, and administration guidelines.
Pinyin Name: Jiānɡ Cán or Bái Jiānɡ Cán
Insect Description: Commonly known as Sāng Cán or Jiā Cán É (silkworm moth), it is a silk-producing insect. Both male and female moths are densely covered with white scales. Body length measures 1.6–2.3 cm; wingspan ranges from 3.9–4.3 cm. The forewings are yellowish-white to ash-gray (grayish-white); the apical margin of the forewing is concave posteriorly; transverse lines are slightly darker but inconspicuous; the terminal line and veins (pterostigma) are taupe (dusty gray). The hindwings are paler than the forewings, and the marginal scale hairs (cilia) are slightly longer. The female abdomen is stout and blunt-ended; the male abdomen is narrower and slightly pointed. Its larva—the silkworm—exhibits body coloration ranging from ash-gray (grayish-white) to white; the second and third thoracic segments are slightly enlarged and wrinkled; the eighth abdominal segment bears a caudal horn. It is cultivated across most regions of China.
Larva:The larva has a long, cylindrical shape composed of three parts: the head, the chest, and the abdomen. The head is covered with a taupe, bony shell. The thorax has one pair of legs in each of the three segments. The abdomen has 10 segments, each with four pairs of gastropods and one pair of tail pedis. One pair of valves is located on each side of the first thoracic segment, and one to eight ventral segments are present. Newly hatched larvae are covered with black and brown bristles and are as small as ants. They are known as silkworms. Silkworms feed on mulberry leaves and grow quickly. Their body color gradually turns green and white.
Egg: The egg is oval and slightly flattened. It is about 1.3 mm long, 1.1-1.2 mm wide, and 0.5-0.6 mm thick. One end is slightly blunt and the other end is slightly pointed. The tip of the egg has a hole that serves as a fertilization channel. Egg size varies with silkworm species, feeding conditions, and pupal temperature. Eggs generally weigh between 500 and 600 micrograms. When first laid, the eggs are faint yellow with a raised surface. Due to the evaporation of water and consumption of nutrients inside the eggs, a depression forms in the middle of the egg surface called the egg vortex. A normal egg is oval, while a dead egg is triangular. The surface of the eggshell is uneven with a polygonal texture and countless needle-like breathing pores. The egg's contents are the yolk membrane, serous membrane, yolk, and embryo. The yolk membrane, which is a layer of transparent, non-cellular film, is close to the undersurface of the eggshell. The serous membrane, which is a layer of large, flat, polygonal cells, is on the inside. The yolk provides nutrients for embryo development. The embryo develops gradually by ingesting nutrients from the yolk inside the egg, with its head toward the foramen.
Characteristics of the Herb: The herb is slightly cylindrical, mostly bent and shriveled, 2–5 cm long, and 0.5–0.7 cm in diameter. The surface is sallow (grayish-yellow), covered with white powdery and creamy aerial hyphae and conidiospores. The head is circular (roundish), with 8 pairs of pedicels; somites are conspicuous, and the tail is slightly dichotomous. The texture of the herb is hard and brittle, easy to break; the fracture surface is flat, the outer layer is white and mealy, and the center is bright brown or coracinus (glossy black), commonly known as “glue-mouth mirror”. It contains four silk gland rings internally, which appear as bright rings. The herb has a slightly fishy odor and tastes slightly salty.
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