In recent decades, a growing body of literature has indicated that microbial symbionts of insects can modulate their hosts' chemical profiles and mate choice decisions. However, there is currently little direct evidence indicate that insect pheromones can be produced by symbionts.Using Bactrocera dorsalis as a model system, we demonstrate that Bacillus sp. in the rectum of male B. dorsalis plays a pivotal role in sex pheromones production. We demonstrate that 2,3,5-trimethylpyrazine (TMP) and 2,3,5,6-tetramethylpyrazine (TTMP) are sex pheromones produced in the male rectums. Mature virgin females can be strongly attracted by TMP and TTMP.TMP and TTMP contents in male rectums can be decreased when rectal bacteria are inhibited with antibiotics. Moreover, Bacillus sp. isolated from male rectum can produce TMP and TTMP when providing with substrates-glucose and threonine, for which the contents are significantly higher in rectums of mature males. These findings highlight the influence of microbial symbionts on insect pheromones and provide an example of direct bacterial production of pheromones in insects.

No abstract

In recent decades, a growing body of literature has indicated that microbial symbionts of insects can modulate their hosts’ chemical profiles and mate choice decisions. However, there is currently little direct evidence indicate that insect pheromones can be produced by symbionts. Using Bactrocera dorsalis as a model system, we demonstrate that Bacillus sp. in the rectum of male B. dorsalis plays a pivotal role in sex pheromones production. We demonstrate that 2,3,5-trimethylpyrazine (TMP) and 2,3,5,6-tetramethylpyrazine (TTMP) are sex pheromones produced in the male rectums. Mature virgin females can be strongly attracted by TMP and TTMP. TMP and TTMP contents in male rectums can be decreased when rectal bacteria are inhibited with antibiotics. Moreover, Bacillus sp. isolated from male rectum can produce TMP and TTMP when providing with substrates-glucose and threonine, for which the contents are significantly higher in rectums of mature males. These findings highlight the influence of microbial symbionts on insect pheromones and provide an example of direct bacterial production of pheromones in insects.

Compound freeform surfaces are widely used in bionic and optical applications. The manufacturing and measurement of such surfaces are challenging due to the complex geometry with multi-scale features in a high precision level with sub-micrometer form accuracy and nanometer surface finish. This article presents a study of ultra-precision machining and characterization of compound freeform surfaces. A hybrid machining process by combining slow slide servo and fast tool servo is proposed to machine compound freeform surfaces. The machining process for this hybrid tool servo is explained, and tool path generation is presented. Then, a normal template-based matching and characterization method is proposed to evaluate such compound freeform surfaces. Experimental studies are undertaken to machine a compound freeform surface using the proposed method based on a four-axis ultra-precision machine tool. The machined compound freeform surface is also measured and characterized by the proposed analysis and characterization method. The experimental results are presented, and the machining errors for compound freeform surfaces are also discussed.