Introduction
Feeding insects to insectivorous and omnivorous lizards is a common practice, but providing a balanced diet requires understanding the nutritional needs of your reptile. This guide covers feeder insect selection, gut-loading, dusting, portion sizes, feeding frequency, and common mistakes to ensure your lizard thrives.
Recommended Feeder Insects
Variety is key to a nutritious diet. Common feeder insects include:
- Crickets – High protein, low fat. Gut-load with calcium-rich foods.
- Dubia Roaches – Excellent protein to fat ratio, high digestibility.
- Mealworms – High fat, feed sparingly. May cause impaction if fed whole to small lizards.
- Superworms – Larger, higher fat than mealworms. Suitable for larger lizards.
- Black Soldier Fly Larvae – Rich in calcium, low fat. Good for growing lizards.
- Waxworms – Very high fat, treat only.
- Silkworms – High protein, low fat, soft-bodied. Excellent for all lizards.
- Hornworms – High moisture, moderate protein. Good for hydration.
Gut-Loading and Dusting
Gut-Loading
Gut-loading involves feeding nutritious foods to insects 24-48 hours before offering them to your lizard. This boosts the nutrient content of the insects. Recommended gut-loading foods:
- Leafy greens (collard, mustard, dandelion)
- Carrots, sweet potatoes
- Commercial gut-load diets
- Calcium-fortified orange cubes or water gels
Avoid gut-loading with low-nutrient foods like potatoes or iceberg lettuce.
Dusting
Dusting involves coating insects with a supplement powder just before feeding. Essential supplements:
- Calcium powder (with D3) – For most lizards, dust every feeding for juveniles, 2-3 times per week for adults.
- Multivitamin powder – Dust once or twice a week.
- Use a separate container for dusting to avoid insect escape.
Portion Sizes and Daily Caloric Needs
Portion sizes vary by species, age, and activity level. As a general guideline:
| Lizard Type | Feeder Insect Size | Insects per Feeding | Feeding Frequency |
|---|---|---|---|
| Juvenile (growing) | Small (< half head width) | 10-20 small insects | Daily |
| Adult (maintenance) | Medium (< head width) | 5-10 medium insects | Every other day |
| Large insectivores (e.g., tegu) | Large (up to head width) | 10-20 large insects | 2-3 times per week |
Monitor body condition: a healthy lizard has a slight rounded belly but no visible fat pads. Overfeeding leads to obesity, especially with high-fat insects.
Feeding Frequency and Schedule
- Juveniles: Feed once daily, as many insects as they can eat in 10-15 minutes.
- Adults: Feed every 1-2 days. Offer insects in a bowl or release a few at a time.
- Timing: Feed during active hours (diurnal lizards in the morning, nocturnal in evening). Remove uneaten insects after 15-20 minutes to prevent stress or injury.
Essential Nutrients
Lizards require a balance of macronutrients and micronutrients.
- Protein: Critical for growth and repair. Feeder insects provide 15-25% protein.
- Fat: Energy source. Too much can cause obesity. Aim for 10-15% fat in diet.
- Calcium to Phosphorus Ratio: Ideal ratio is 2:1. Most insects are low in calcium and high in phosphorus, so dusting and gut-loading are crucial.
- Vitamin D3: Required for calcium absorption. UVB lighting or dietary D3 needed.
- Other Vitamins: A, E, B-complex via gut-loading and multivitamins.
Toxic Foods and Ingredients
Never feed the following to lizards or to feeder insects intended for lizards:
- Avocado – Contains persin, toxic to reptiles.
- Rhubarb – High oxalates, can bind calcium.
- Onions, Garlic, Chives – Can cause hemolytic anemia.
- Spinach, Beet Greens (in large amounts) – High oxalates.
- Iceberg Lettuce – Low nutrient value, can cause diarrhea.
- Wild-caught insects – May carry pesticides or parasites.
Hydration
Provide fresh water daily in a shallow dish. Many lizards obtain moisture from gut-loaded insects (e.g., hornworms). Misting the enclosure or offering water droplets on leaves can encourage drinking. Signs of dehydration: sunken eyes, wrinkled skin, lethargy.
Supplements
In addition to dusting, consider:
- Calcium without D3 – For lizards with adequate UVB.
- Beta-carotene – Precursor to vitamin A, especially for insectivores.
- Probiotics – May aid digestion, especially when on antibiotics.
- Consult a vet before adding supplements beyond routine calcium and multivitamins.
Differences by Age
Juveniles
Require more frequent feeding (daily) and higher calcium to support rapid bone growth. Dust all insects with calcium. Offer smaller insects to prevent impaction.
Adults
Maintenance diet. Reduce feeding frequency to prevent obesity. Continue calcium dusting but less frequently. Monitor weight and adjust portions.
Seniors
May have reduced activity. Offer smaller and softer insects (silkworms, phoenix worms). Ensure easy access to water. Watch for dental issues or decreased appetite.
Signs of Healthy vs. Poor Diet
Healthy Diet Indicators
- Bright eyes, clear skin
- Good muscle tone, well-fleshed tail
- Regular defecation (undigested insect parts in stool)
- Active and alert
- Shedding normally
Poor Diet Indicators
- Weight loss or obesity
- Soft or deformed bones (metabolic bone disease)
- Lethargy, loss of appetite
- Abnormal feces (diarrhea, undigested food)
- Difficulty shedding
- Swollen limbs or jaw
If any signs of poor health appear, consult a reptile veterinarian. Adjust diet, supplement routine, and husbandry as needed.