Effect of the energy content of diets on the development and quality of the fat reserves of larvae and reproduction of adults of the black soldier fly, Hermetia illucens (Diptera: Stratiomyidae)

Abstract

Hermetia illucens is a sustainable and an increasingly bioeconomical source of nutrients for farm animals. It is still necessary, however, to improve our knowledge of the biological features of this species in order to maximize its use. The aims of this research were to evaluate the effect of the energy level of rearing diets on its body weight and fat-body reserves. The quantity and quality of the fats storred by the non-feeding stages of this insect and its reproductive performances were also studied. A control diet (CD -Gainesville diet) and three diets with progressively greater energy contents (kcal/kg ME) were formulated. The increase was achieved by including different amounts of maize, 40% (ED 1 ), 60% (ED 2 ) and 80% (ED 3 ), in these three diets. Abother diet (ED 4 ) consisted of fruit and vegetable waste. The results indicate that the body weight of larvae, prepupae, pupae and adult fl ies, as well as fat content of the larvae increased signifi cantly (p ˂ 0.01) with increase in the energy content of the diets. There was a positive Pearson correlation between energy content of diets and body weight of adult fl ies. The heaviest egg clutches with the highest number of eggs/clutch (p ˂ 0.01) were laid by fl ies reared on the diets with the highest energy content. The quality of the fat stored by larvae did not infl uence the weight and number of egg laid.

Determination of lipid requirements in black soldier fly through semi-purified diets

“…The human error was excluded as an influencing factor as the standard error value maintained high at T2 and T3, as well as for the prepupae weight. From a nutritional point of view (lipid and protein content), the L3.5 dietary treatment is partially comparable to the ED 1 diet formulated by Georgescu et al 26 . Already at 10 days of age, the L3.5 larvae were smaller than ED 1 (0.105 mg and about 0.162 mg, respectively).…”

“…In recent years, research has started to focus the attention on the BSF nutritional requirements determination. In particular, studies related to protein, energy and carbohydrate needs have recently been carried out 23 , 26 , 27 . The knowledge on BSF nutrient requirements is still limited, even if the great number of scientific papers published on its life cycle and its use as feed ingredient 28 – 30 .…”

“…The difference between the two studies may be due to the different carbohydrate percentage or to the quality of the supplied macronutrients. In particular, in semi-purified diets macronutrients are present almost in purity when compared to the ingredients of GA and soybean meal used by Georgescu et al 26 . Finally, considering that the marked difference recorded at T1 among the treatment with the highest lipid content and the others was lost at T2 and T3, it is possible to hypothesize that the lipid requirement is highest in early larval stages.…”

A Comprehensive Method for the Evaluation of Hermetia illucens Egg Quality Parameters: Implications and Influence Factors

“…The increased number of eggs in the clutch is correlated with the increase in weight, the differences between the different categories of clutches being statistically supported (Table 1). Our previous research demonstrated that these aspects depend on different experimental factors and/or treatments applied in larval feeding [14,17]. Egg length and width increase gradually and constantly from one egg clutch category to another.…”

“…The capacity of ovipositing the eggs [11] is of paramount importance. The insect can reproduce only once; after the adult fly emerges, the accumulated energy reserves support the metabolic requirements of mating and egg laying [12][13][14]. Females generally lay between 300 and 1000 eggs [10,11,15], but the eggs number may be higher depending on the larval rearing medium [16,17].…”