The study was carried out in Laboratoire d’Entomologie Fondamentale et Appliquée (LEFA) of Université Joseph KI-ZERBO (Ouagadougou, Burkina Faso). The mean temperature was 27.51˚C ± 2.34˚C and relative humidity ranged to 46.76% ± 15.27%. The duration of the experiment was 80 days.

The animal material used was C. serratus individuals from Manga’s zone. This strain of C. serratus was isolated from naturally infested T. indica pods in this zone. These strains were maintained through successive rearing on tamarind from the same area in the Laboratoire d’Entomologie Fondamentale et Appliquée (LEFA) of Université Joseph KI-ZERBO Université (Ouagadougou, Burkina Faso).

The plant material used for this study consisted of T. indica pods. These tamarind pods were purchased with the women in the Manga’s zone. Once transported in the laboratory, T. indica pods were first sorted to exclude those with holes or rotting. They were then placed in a freezer at −18˚C in the Laboratoire d’Entomologie Fondamentale et Appliquée (LEFA) of Université Joseph KI-ZERBO Université (Ouagadougou, Burkina Faso) in order to eliminate any previous infestation.

100 healthy T. indica pods were placed in contact with ten pairs of C. serratus for 24 hours for oviposition. The adults were then removed and 25 pods, each carrying a maximum of two eggs, were distributed in 450 ml dishes, in five batches of 5 pods each, in 5 replicate. The batches of pods thus formed were placed in incubation until the embryo appears inside the chorion. The boxes were daily removed and the pods they contained were individually observed under a Leica binocular loupe to count the number of eggs containing an embryo. The pods carrying these eggs were then removed from the boxes. The incubation time during this study was 13 days. The embryonated egg shows a reddish spot representing the embryo’s head capsule.

As soon as the new generation of insects appeared, a pair of C. serratus aged less than 24 h was placed in contact with 4 healthy pods for 24 h in a 450 ml dish. Every day, the pair was removed and transferred to another box containing 4 new healthy pods until the female died. All boxes were then incubated in the laboratory at a temperature of 27.51˚C ± 2.34˚C and relative humidity of 46.76% ± 15.27%. A total of 20 replicates were carried out in order to increase the precision and validity of the significance test. After the withdrawal of each pair, the eggs laid daily by the female were counted; the number of hatched and unhatched eggs was also counted daily until the end of hatching. The hatched egg was whitish in color, while the unhatched egg remained translucent [13] . From the onset of emergence until the end, the males and females emerging each day were counted and removed from each box.

Thirty newly-emerged males and thirty newly-emerged females were weighed using a OHAUS brand sensitive scale; their size was also measured using software associated with a LEICA magnifying glass. The number of cocoons formed and the number of larvae unable to weave a cocoon were counted.

A pod can be considered healthy when it is neither damaged nor contains another form of life (eggs, larvae or insects).

At the end of monitoring, the following parameters are evaluated:

· Development time: This is the time between the egg-laying and its emergence as an adult. It is estimated using the following equation:

D D = Σ n i x i Σ x i

xi: number of insects emerging per day; ni: corresponding number of days.

· Intrinsic rate of natural increase (r): It is the rate of population growth attributable to the natural movement of the population. It was obtained through the equation of [14] .

r = ln ( N S ) T + 1 / 2 L

L = female lifespan; N = average number of eggs laid per female; S = larval survival rate; T = development time; ln = natural logarithm.

· Generation time (GT): It reflects the average time between two consecutive generations in the genealogy of a population. It is estimated by the formula of [15] .

GT = T (development time) + average age of a female when all her eggs are laid.

· Population doubling time (D.T.): It is the time required for the population to double in size, it was determined by using [16] formula.

D . T = ln 2 r

The data collected was entered into the Excel 2016 spreadsheet, which was used to make various graphics. Statistical processing of the data was carried out using R software, 4.1.0 version. Statistical tests were performed according to the scheme proposed by [17] .

We first performed a normality test followed by a homogeneity test for all measured variables. Thus, we performed Student’s t-test to compare adult lifespan, number of emerged individuals, height and weight of emerged individuals as a function of sex. The significance level was 5%.

The average lifespan of C. serratus, all sexes combined, was 14 days. However, the average lifespan differed significantly according to sex (t^1;38 = 2.33, P = 0.025). Females lived longer, with an average lifespan of around 16 days, compared with males, who averaged around 13 days (Figure 1).

The eggs laid measure around 1 mm in length and 0.57 mm in width (Table 1). These eggs were deposited on pods averaging 6.66 g and 16.59 cm thick.

The average number of eggs laid by C. serratus’s female during her lifetime was around 34 (Table 2). With a hatching rate of 89.28 ± 9.76, the average number of infertile eggs is 3.85.

C. serratus’s female laid an average of two eggs on the first day. The number of eggs laid increases until it reaches a maximum peak on the 4^th day, then gradually decreases until day 14, after which no more eggs were laid (Figure 2).

It is estimated that 66.63% of eggs laid gave rise to adults, i.e. 22 individuals per female. This means that 17.12% of larvae from C. serratus eggs failed to reach the adult stage and thus died at the larval stage (Table 3). We can see that the

embryo is established as early as the 3^rd day, and the incubation time extends over 9 days. The total development of C. serratus in our study took around 64 days (Table 3).

When larvae reached the 4^th stage, they used the seed to weave a cocoon to complete their development cycle. While 83% of larvae from hatched eggs were able to weave cocoons, the remainders were unable to continue their development, i.e. around 8% died inside the seed and 9% outside (Table 4).

88.69% of the larvae that were able to weave a cocoon were able to complete their development by emerging to give birth to adults (Figure 3). However, 11.31% were unable to reach the last phase of their development and thus died inside the cocoons. Cocoons formed by C. serratus larvae average 6.78 mm in length and 4.19 mm in width.

Analysis of Table 5 shows that there was no significant difference between the number of males and females emerged; however, there was a sex ratio of 0.96 in favor of females. However, the weight and size of the females resulting from this emergence differed significantly from those of the males.

With a generation time of around 79 days, C. serratus population doubles in size in 5.68 days, for an intrinsic rate of natural increase of 0.12 (Table 6).

The means followed by different alphabetic letters in the same lines are significantly different (P < 0.05, Student Newmann Keuls’s test).