## 3 Results
### Lethal Time (LT)  
Both EPF here studied infect their hosts until they cause the death of the organism, as mentioned above. Although infection can occur at various points on the cuticle, this study observed a preference for central and peripheral sites in _A. mexicana_. Probit transformation was used to determine the median lethal time (LT\({}_{50}\)) of the most virulent biopreparations. Highly significant differences were observed (ANOVA: F = 7891.20, \(p\) = 0.001). The estimated time required to kill 50% of the individuals was 48 h for the biopreparations MA-Bb1+Diatomin(r) and MA-Bb1. Conversely, the _M. anisopliae(r)_ and _B. bassiana(r)_ biopreparations showed a median lethal concentration (LT\({}_{50}\)) of 72 h (Table 3), with no significant statistical differences in this case. According to the results presented in Table 3, the MA-Bb1+Diatomin(r) biopreparation exhibited the shortest LT\({}_{80}\), with a duration of 72 h, followed by the MA-Bb1 treatment, which presented an LT\({}_{80}\) of 96 h. In contrast, the _M. anisopliae, B. bassiana(r)_, and Diatomin(r) treatments showed an LT\({}_{80}\) of 120 h each. A strong positive correlation was observed between the variables LT\({}_{50}\), LT\({}_{80}\), and time of mycosis manifestation, indicating that treatment with the different biopreparation formulations showed a high positive correlation with the mortality of _A. mexicana_ in vivo (Table 4). Additionally, survival was negatively correlated with the variables LT\({}_{50}\), LT\({}_{80}\), and time of mycosis manifestation after treatment with the different biopreparation formulations. The shortest time of mycosis manifestation in the ants presented highly significant differences (ANOVA: F = 36.92, \(p\) = 0.001). The MA-Bb1+Diatomin(r) biopreparation achieved mycelial coating 312 h post inoculation under in vitro conditions, followed by the _B. bassiana_ (MA-Bb1) biopreparation, which induced mycelial coating 384 h after inoculation. The _M. anisopliae(r)_ biopreparation required the shortest time (576 h) to induce mycelial coating in _A. mexicana_. \begin{table}
\begin{tabular}{c c c c c c c} \hline
**Treatments** & **LT\({}_{50}\) (Hours *)** & **CI of 95\%** & **\(p\) Value** & **LT\({}_{80}\) (Hours *)** & **CI of 95\%** & **\(p\) Value** \\ \hline _Beautveria bassiana_ MA-Bb1 & 48 a & 43.37–54.62 & 0.001 & 96 b & 94.7–97.2 & 0.001 \\ _B. bassiana_ MA-Bb1+Diatomin® & 48 a & 43.34–52.65 & 0.001 & 72 a & 70.7–73.2 & 0.001 \\ _* B. bassiana®_ & 72 c & 64.03–79.96 & 0.001 & 120 c & 118.7–121.2 & 0.001 \\ _+ M. anisopliae®_ & 72 c & 63.33–80.66 & 0.001 & 120 c & 118.7–121.2 & 0.001 \\ Diatomin® & 96 d & 89.45–102.54 & 0.001 & 120 c & 119.7–122.2 & 0.001 \\ Tween 80 (0.01\%) & 192 e & 177.74–206.25 & 0.001 & 264 d & 262.7–265.2 & 0.001 \\ \hline \end{tabular}  
* Equal letters indicate that there are no statistically significant differences (\(p\) < 0.05) according to [PERSON]’s test between treatments. CI = confidence interval.  
\end{table} 
Table 3: Lethal time of _A. mexicana_ when exposed to different biopreparations. Figure 1: Total mortality (%) of _A. mexicana_ in different biopreparations 96 h after in vitro inoculation. Equal letters indicate that there are no statistically significant differences (\(p\) < 0.05) according to the Tukey test between treatments. Error bars (EB) = standard deviation. Studies carried out with a scanning electron microscope (SEM) provided information on the infection and colonization of _A. mexicana_ by EPF. The observations included the identification of a mycelial network with conidial balls (Figure 2A,B), featuring globose conidia arranged on the mesosome's cuticle. This characteristic is typical of _B. bassiana_ and was observed across the insect's body, resulting in a mummified appearance of the host. The microscopic analysis also confirmed the adherence of the Diatomin(r) treatment to most of the insect's body, with a more pronounced presence around the head of _A. mexicana_ (Figure 2C) and the compound eye (Figure 2D). Additionally, extensive networks of _B.